Allow search usages for declarations when correct isEquivalentTo

Now it's possible to do find usages for other languages when light
elements are used.

Revert efb36f4a49 and revise fix of KT-7983:
Don't consider local and non-local class with same fqn equivalent.

 #KT-7983 Fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/references/referenceUtil.kt

@@ -86,7 +86,11 @@ fun PsiReference.matchesTarget(candidateTarget: PsiElement): Boolean {
     }
 
     val targets = unwrappedTargets
-    if (unwrappedCandidate in targets) return true
+
+    val manager = candidateTarget.manager
+    if (targets.any { manager.areElementsEquivalent(unwrappedCandidate, it) }) {
+        return true
+    }
 
     if (element is KtLabelReferenceExpression && (element.parent as? KtContainerNode)?.parent is KtReturnExpression) {
         targets.forEach {
@@ -97,9 +101,6 @@ fun PsiReference.matchesTarget(candidateTarget: PsiElement): Boolean {
         }
     }
 
-    // TODO: Investigate why PsiCompiledElement identity changes
-    if (unwrappedCandidate is PsiCompiledElement && targets.any { it.isEquivalentTo(unwrappedCandidate) }) return true
-
     if (this is KtReference) {
         return targets.any {
             it.isConstructorOf(unwrappedCandidate)