Return kotlin ctor mapped to a java ctor even if java ctor is synthetic

This allows working with constructors with inline class parameters using
Kotlin reflection, as described in
https://youtrack.jetbrains.com/issue/KT-27429#focus=streamItem-27-3161148-0-0

 #KT-27913
 #KT-27429

compiler/testData/codegen/box/reflection/mapping/constructorWithInlineClassParameters.kt

@@ -0,0 +1,21 @@
+// IGNORE_BACKEND: JVM_IR, JS_IR, JS, NATIVE
+// WITH_REFLECT
+import kotlin.reflect.full.primaryConstructor
+import kotlin.reflect.jvm.javaConstructor
+import kotlin.reflect.jvm.kotlinFunction
+import kotlin.test.assertEquals
+
+inline class Z(val x: Int)
+
+class Test(val x: Z)
+
+fun box(): String {
+    val kctor1 = Test::class.primaryConstructor ?: throw AssertionError("No primary constructor")
+    val jctor1 = kctor1.javaConstructor ?: throw AssertionError("No javaConstructor for $kctor1")
+    val kctor2 = jctor1.kotlinFunction ?: throw AssertionError("No kotlinFunction for $jctor1")
+
+    assertEquals(kctor1, kctor2)
+    assertEquals("[x]", kctor2.parameters.map { it.name }.toString())
+
+    return "OK"
+}

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

@@ -20200,6 +20200,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 runTest("compiler/testData/codegen/box/reflection/mapping/constructor.kt");
             }
 
+            @TestMetadata("constructorWithInlineClassParameters.kt")
+            public void testConstructorWithInlineClassParameters() throws Exception {
+                runTest("compiler/testData/codegen/box/reflection/mapping/constructorWithInlineClassParameters.kt");
+            }
+
             @TestMetadata("extensionProperty.kt")
             public void testExtensionProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/reflection/mapping/extensionProperty.kt");

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

@@ -20200,6 +20200,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 runTest("compiler/testData/codegen/box/reflection/mapping/constructor.kt");
             }
 
+            @TestMetadata("constructorWithInlineClassParameters.kt")
+            public void testConstructorWithInlineClassParameters() throws Exception {
+                runTest("compiler/testData/codegen/box/reflection/mapping/constructorWithInlineClassParameters.kt");
+            }
+
             @TestMetadata("extensionProperty.kt")
             public void testExtensionProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/reflection/mapping/extensionProperty.kt");

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

@@ -20205,6 +20205,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/reflection/mapping/constructor.kt");
             }
 
+            @TestMetadata("constructorWithInlineClassParameters.kt")
+            public void testConstructorWithInlineClassParameters() throws Exception {
+                runTest("compiler/testData/codegen/box/reflection/mapping/constructorWithInlineClassParameters.kt");
+            }
+
             @TestMetadata("extensionProperty.kt")
             public void testExtensionProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/reflection/mapping/extensionProperty.kt");

core/reflection.jvm/src/kotlin/reflect/jvm/ReflectJvmMapping.kt

@@ -144,7 +144,5 @@ val Method.kotlinFunction: KFunction<*>?
  */
 val <T : Any> Constructor<T>.kotlinFunction: KFunction<T>?
     get() {
-        if (isSynthetic) return null
-
         return declaringClass.kotlin.constructors.firstOrNull { it.javaConstructor == this }
     }

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/IrJsCodegenBoxTestGenerated.java

@@ -17665,6 +17665,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/reflection/mapping/constructor.kt");
             }
 
+            @TestMetadata("constructorWithInlineClassParameters.kt")
+            public void testConstructorWithInlineClassParameters() throws Exception {
+                runTest("compiler/testData/codegen/box/reflection/mapping/constructorWithInlineClassParameters.kt");
+            }
+
             @TestMetadata("extensionProperty.kt")
             public void testExtensionProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/reflection/mapping/extensionProperty.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -18720,6 +18720,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/reflection/mapping/constructor.kt");
             }
 
+            @TestMetadata("constructorWithInlineClassParameters.kt")
+            public void testConstructorWithInlineClassParameters() throws Exception {
+                runTest("compiler/testData/codegen/box/reflection/mapping/constructorWithInlineClassParameters.kt");
+            }
+
             @TestMetadata("extensionProperty.kt")
             public void testExtensionProperty() throws Exception {
                 runTest("compiler/testData/codegen/box/reflection/mapping/extensionProperty.kt");