[reflect] Fix flaky tests that depend on Reflection.clearCaches()

* Use ReflectionFactoryImpl as single point of synchronization
* Synchronize all cache-sensitive tests on it in order to be robust in parallel test runners
* Remove redundant cache clear after each test

Merge-request: KT-MR-6842
Merged-by: Vsevolod Tolstopyatov <qwwdfsad@gmail.com>

compiler/testData/codegen/box/reflection/jvmKPackageCaching.kt

@@ -2,12 +2,15 @@
 // FULL_JDK
 // WITH_REFLECT
 import kotlin.jvm.internal.*
+import kotlin.reflect.jvm.internal.*
 
 class A
 fun box(): String {
-    val pckg = Reflection.getOrCreateKotlinPackage(A::class.java)
-    System.gc()
-    val pckg2 = Reflection.getOrCreateKotlinPackage(A::class.java)
-    if (pckg === pckg2) return "OK"
-    return "Fail"
+    return synchronized(ReflectionFactoryImpl::class.java) {
+        val pckg = Reflection.getOrCreateKotlinPackage(A::class.java)
+        System.gc()
+        val pckg2 = Reflection.getOrCreateKotlinPackage(A::class.java)
+        if (pckg === pckg2) return@synchronized "OK"
+        return@synchronized "Fail"
+    }
 }

compiler/testData/codegen/box/reflection/jvmKTypeCaching.kt

@@ -1,13 +1,16 @@
 // TARGET_BACKEND: JVM_IR
 // FULL_JDK
 // WITH_REFLECT
+import kotlin.reflect.jvm.internal.*
 
 class A
 
 fun box(): String {
-    val clz = A::class
-    System.gc()
-    val clz2 = A::class
-    if (clz === clz2) return "OK"
-    return "Fail"
+    return synchronized(ReflectionFactoryImpl::class.java) {
+        val clz = A::class
+        System.gc()
+        val clz2 = A::class
+        if (clz === clz2) return@synchronized "OK"
+        return@synchronized "Fail"
+    }
 }

compiler/testData/codegen/box/reflection/methodsFromAny/parametersEqualsWithClearCaches.kt

@@ -12,7 +12,9 @@ inline fun check(message: String, generate: () -> Any?) {
         x1 = generate()
 
         // Force clear the internal maps, as if the weak values in them are garbage-collected.
-        kotlin.reflect.jvm.internal.ReflectionFactoryImpl.clearCaches()
+        synchronized(kotlin.reflect.jvm.internal.ReflectionFactoryImpl::class.java) {
+            kotlin.reflect.jvm.internal.ReflectionFactoryImpl.clearCaches()
+        }
 
         x2 = generate()
     } catch (e: Throwable) {

compiler/testData/codegen/box/reflection/methodsFromAny/typeParametersEqualsWithClearCaches.kt

@@ -11,7 +11,9 @@ inline fun check(message: String, generate: () -> Any?) {
         x1 = generate()
 
         // Force clear the internal maps, as if the weak values in them are garbage-collected.
-        kotlin.reflect.jvm.internal.ReflectionFactoryImpl.clearCaches()
+        synchronized(kotlin.reflect.jvm.internal.ReflectionFactoryImpl::class.java) {
+            kotlin.reflect.jvm.internal.ReflectionFactoryImpl.clearCaches()
+        }
 
         x2 = generate()
     } catch (e: Throwable) {

compiler/testData/codegen/box/reflection/typeOf/caching.kt

@@ -5,6 +5,7 @@ import kotlin.test.assertEquals
 import kotlin.test.assertSame
 import kotlin.reflect.KType
 import kotlin.reflect.typeOf
+import kotlin.reflect.jvm.internal.*
 
 private inline fun <reified T> check(isNullable: Boolean = false) {
     val t1 = typeOf<T>()
@@ -15,10 +16,12 @@ private inline fun <reified T> check(isNullable: Boolean = false) {
 }
 
 fun box(): String {
-    check<Int>()
-    check<Int?>(true)
-    check<List<Int>?>(true)
-    check<List<Int>>()
-    check<List<Int?>?>(true)
+    synchronized(ReflectionFactoryImpl::class.java) {
+        check<Int>()
+        check<Int?>(true)
+        check<List<Int>?>(true)
+        check<List<Int>>()
+        check<List<Int?>?>(true)
+    }
     return "OK"
 }