FIR nested classifier scope building: optimize companion search

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirAbstractTreeTransformerWithSuperTypes.kt

@@ -41,8 +41,8 @@ abstract class FirAbstractTreeTransformerWithSuperTypes(
                     nestedClassifierScope(it.lookupTag.classId, session)
                 }
             regularClass.addTypeParametersScope()
-            val companionObjects = regularClass.declarations.filterIsInstance<FirRegularClass>().filter { it.isCompanion }
-            for (companionObject in companionObjects) {
+            val companionObject = regularClass.companionObject
+            if (companionObject != null) {
                 towerScope.scopes += nestedClassifierScope(companionObject)
             }
             towerScope.scopes += nestedClassifierScope(regularClass)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirDeclarationsResolveTransformer.kt

@@ -231,8 +231,8 @@ class FirDeclarationsResolveTransformer(transformer: FirBodyResolveTransformer)
             if (regularClass.symbol.classId.isLocal) {
                 prepareLocalClassForBodyResolve(regularClass)
             }
-            val companionObjects = regularClass.declarations.filterIsInstance<FirRegularClass>().filter { it.isCompanion }
-            for (companionObject in companionObjects) {
+            val companionObject = regularClass.companionObject
+            if (companionObject != null) {
                 topLevelScopes += nestedClassifierScope(companionObject)
             }
             topLevelScopes += nestedClassifierScope(regularClass)