Shift ReferencesToSyntheticJavaProperties feature release from 1.9 to 2.1

Other related tests:
- testGenericJavaProperty
- testFunInterfaceConstructorReference

Meta issue: KT-8575
Review: https://jetbrains.team/p/kt/reviews/9595

UnsupportedSyntheticCallableReferenceChecker only existed for K1,
because we wanted to release the feature for 1.9 and the feature should
have been working for K2 unconditionally. But since, we're postponing
the release until 2.1, we also need to port the checker from K1 to K2

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/checkers/UnsupportedSyntheticCallableReferenceChecker.kt

@@ -27,12 +27,16 @@ import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
 import org.jetbrains.kotlin.resolve.calls.util.extractCallableReferenceExpression
 import org.jetbrains.kotlin.synthetic.SyntheticJavaPropertyDescriptor
 
+/**
+ * This is K1 implementation.
+ * For K2 implementation see: [org.jetbrains.kotlin.fir.analysis.jvm.checkers.expression.FirUnsupportedSyntheticCallableReferenceChecker]
+ */
 class UnsupportedSyntheticCallableReferenceChecker : CallChecker {
     override fun check(resolvedCall: ResolvedCall<*>, reportOn: PsiElement, context: CallCheckerContext) {
         // TODO: support references to synthetic Java extension properties (KT-8575)
         val callableReferenceExpression = resolvedCall.call.extractCallableReferenceExpression() ?: return
 
-        // We allow resolve of top-level callable reference to synthetic Java extension properties in delegate position
+        // We allow resolution of top-level callable references to synthetic Java extension properties in the delegate position. See KT-47299
         if (callableReferenceExpression.unwrapParenthesesLabelsAndAnnotationsDeeply() is KtPropertyDelegate) return
 
         if (resolvedCall.resultingDescriptor is SyntheticJavaPropertyDescriptor) {