Use Class.forName instead of ClassLoader.loadClass in reflection

This fixes an issue in constructing annotation instances with array
class elements. For some reason, behavior of `ClassLoader.loadClass`
differs from `Class.forName` in handling arrays, namely:

* `loadClass("[Ltest.Foo;")` returns null
* `Class.forName("[Ltest.Foo;")` returns class for array of test.Foo

Overall, there doesn't seem to be any way to load an array class with
`CLassLoader.loadClass`.

We pass initialize=false to forName because this is the behavior of
ClassLoader.loadClass: it doesn't perform class initialization (e.g.
<clinit> is not executed).

 #KT-31318 Fixed

compiler/testData/codegen/box/reflection/annotations/onTypes/arrayKClass.kt

@@ -0,0 +1,14 @@
+// TARGET_BACKEND: JVM
+// WITH_REFLECT
+
+import kotlin.reflect.KClass
+
+@Target(AnnotationTarget.TYPE)
+annotation class MyAnn(val cls: KClass<*>)
+
+val s: @MyAnn(Array<String>::class) String = ""
+
+fun box(): String {
+    val ann = ::s.returnType.annotations[0] as MyAnn
+    return if (ann.cls == Array<String>::class) "OK" else "Fail: ${ann.cls}"
+}

compiler/testData/codegen/box/reflection/annotations/onTypes/differentArgumentTypes.kt

@@ -58,7 +58,7 @@ fun f(): @Anno(
     AnnotationTarget.EXPRESSION,
     Nested("1"),
     ["lmao"],
-    [Double::class, Unit::class, LongArray::class],
+    [Double::class, Unit::class, LongArray::class, Array<String>::class],
     [AnnotationTarget.TYPEALIAS, AnnotationTarget.FIELD],
     [Nested("2"), Nested("3")]
 ) Unit {}
@@ -67,9 +67,9 @@ fun box(): String {
     assertEquals(
         "[@Anno(b=1, c=x, d=3.14, f=-2.72, i=42424242, j=239239239239239, s=42, z=true, " +
                 "ba=[-1], ca=[y], da=[-3.14159], fa=[2.7218], ia=[424242], ja=[239239239239], sa=[-43], za=[false, true], " +
-                "str=lol, k=class java.lang.Number, k2=class [I, e=EXPRESSION, a=@Nested(value=1), " +
+                "str=lol, k=class java.lang.Number, k2=class [I, e=EXPRESSION, a=@Nested(value=1), stra=[lmao], " +
-                "stra=[lmao], ka=[class java.lang.Double, class kotlin.Unit, class [J], ea=[TYPEALIAS, FIELD], " +
+                "ka=[class java.lang.Double, class kotlin.Unit, class [J, class [Ljava.lang.String;], " +
-                "aa=[@Nested(value=2), @Nested(value=3)])]",
+                "ea=[TYPEALIAS, FIELD], aa=[@Nested(value=2), @Nested(value=3)])]",
         ::f.returnType.annotations.toString()
     )
 

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -20083,6 +20083,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                     KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/box/reflection/annotations/onTypes"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.JVM, true);
                 }
 
+                @TestMetadata("arrayKClass.kt")
+                public void testArrayKClass() throws Exception {
+                    runTest("compiler/testData/codegen/box/reflection/annotations/onTypes/arrayKClass.kt");
+                }
+
                 @TestMetadata("classLiteralWithExpectedType.kt")
                 public void testClassLiteralWithExpectedType() throws Exception {
                     runTest("compiler/testData/codegen/box/reflection/annotations/onTypes/classLiteralWithExpectedType.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -20083,6 +20083,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                     KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/box/reflection/annotations/onTypes"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.JVM, true);
                 }
 
+                @TestMetadata("arrayKClass.kt")
+                public void testArrayKClass() throws Exception {
+                    runTest("compiler/testData/codegen/box/reflection/annotations/onTypes/arrayKClass.kt");
+                }
+
                 @TestMetadata("classLiteralWithExpectedType.kt")
                 public void testClassLiteralWithExpectedType() throws Exception {
                     runTest("compiler/testData/codegen/box/reflection/annotations/onTypes/classLiteralWithExpectedType.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -18973,6 +18973,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                     KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/box/reflection/annotations/onTypes"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.JVM_IR, true);
                 }
 
+                @TestMetadata("arrayKClass.kt")
+                public void testArrayKClass() throws Exception {
+                    runTest("compiler/testData/codegen/box/reflection/annotations/onTypes/arrayKClass.kt");
+                }
+
                 @TestMetadata("classLiteralWithExpectedType.kt")
                 public void testClassLiteralWithExpectedType() throws Exception {
                     runTest("compiler/testData/codegen/box/reflection/annotations/onTypes/classLiteralWithExpectedType.kt");

core/descriptors.runtime/src/kotlin/reflect/jvm/internal/components/ReflectJavaClassFinder.kt

@@ -46,7 +46,7 @@ class ReflectJavaClassFinder(private val classLoader: ClassLoader) : JavaClassFi
 
 fun ClassLoader.tryLoadClass(fqName: String) =
     try {
-        loadClass(fqName)
+        Class.forName(fqName, false, this)
     } catch (e: ClassNotFoundException) {
         null
     }

core/reflection.jvm/src/kotlin/reflect/jvm/internal/util.kt

@@ -90,8 +90,8 @@ private fun loadClass(classLoader: ClassLoader, packageName: String, className:
     }
 
     var fqName = "$packageName.${className.replace('.', '$')}"
-    repeat(arrayDimensions) {
+    if (arrayDimensions > 0) {
-        fqName = "[$fqName"
+        fqName = "[".repeat(arrayDimensions) + "L$fqName;"
     }
 
     return classLoader.tryLoadClass(fqName)