Rename: Fix processing of functions without light methods

#KT-22461 Fixed

idea/testData/refactoring/rename/privateFunInMultifileFacade/after/test.kt

@@ -0,0 +1,9 @@
+@file:JvmMultifileClass()
+@file:JvmName("Bazz")
+package test
+
+private fun bar() { }
+
+fun test() {
+    bar()
+}

idea/testData/refactoring/rename/privateFunInMultifileFacade/before/test.kt

@@ -0,0 +1,9 @@
+@file:JvmMultifileClass()
+@file:JvmName("Bazz")
+package test
+
+private fun /*rename*/foo() { }
+
+fun test() {
+    foo()
+}

idea/testData/refactoring/rename/privateFunInMultifileFacade/privateFunInMultifileFacade.test

@@ -0,0 +1,5 @@
+{
+  "type": "MARKED_ELEMENT",
+  "mainFile": "test.kt",
+  "newName": "bar"
+}