KT-9547: private package member can conflict only with the members

declared in the same file.
Cleanup OverloadUtil stuff.
Update testData.

idea/testData/copyPaste/imports/NoImportForSamePackage.kt

@@ -44,13 +44,13 @@ class ClassObject {
     }
 }
 
-<selection>fun f(p: A, t: T) {
+<selection>private fun f(p: A, t: T) {
     g(A(c).ext())
     O1.f()
     O2
     ENTRY
 }
 
-fun f2(i: Inner, n: Nested, e: NestedEnum, o: NestedObj, t: NestedTrait, a: NestedAnnotation) {
+private fun f2(i: Inner, n: Nested, e: NestedEnum, o: NestedObj, t: NestedTrait, a: NestedAnnotation) {
     ClassObject
 }</selection>