[DLC] add missing identity checks to 'equals'

^KT-56613

analysis/decompiled/light-classes-for-decompiled/src/org/jetbrains/kotlin/analysis/decompiled/light/classes/KtLightFieldForDecompiledDeclaration.kt

@@ -57,7 +57,8 @@ open class KtLightFieldForDecompiledDeclaration(
 
     override fun computeConstantValue(visitedVars: MutableSet<PsiVariable>?): Any? = (fldDelegate as? PsiVariableEx)?.computeConstantValue(visitedVars)
 
-    override fun equals(other: Any?): Boolean = other is KtLightFieldForDecompiledDeclaration &&
+    override fun equals(other: Any?): Boolean = other === this ||
+            other is KtLightFieldForDecompiledDeclaration &&
             name == other.name &&
             fldParent == other.fldParent &&
             fldDelegate == other.fldDelegate

analysis/decompiled/light-classes-for-decompiled/src/org/jetbrains/kotlin/analysis/decompiled/light/classes/KtLightMethodForDecompiledDeclaration.kt

@@ -87,7 +87,8 @@ class KtLightMethodForDecompiledDeclaration(
     override fun getSignature(substitutor: PsiSubstitutor): MethodSignature =
         MethodSignatureBackedByPsiMethod.create(this, substitutor)
 
-    override fun equals(other: Any?): Boolean = other is KtLightMethodForDecompiledDeclaration &&
+    override fun equals(other: Any?): Boolean = other === this ||
+            other is KtLightMethodForDecompiledDeclaration &&
             name == other.name &&
             funParent == other.funParent &&
             funDelegate == other.funDelegate