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.expected.kt

@@ -1,13 +1,13 @@
 // ERROR: No value passed for parameter i
 package a
 
-fun f(p: A, t: T) {
+private fun f(p: A, t: T) {
     g(A(c).ext())
     O1.f()
     O2
     E.ENTRY
 }
 
-fun f2(i: Outer.Inner, n: Outer.Nested, e: Outer.NestedEnum, o: Outer.NestedObj, t: Outer.NestedTrait, a: Outer.NestedAnnotation) {
+private fun f2(i: Outer.Inner, n: Outer.Nested, e: Outer.NestedEnum, o: Outer.NestedObj, t: Outer.NestedTrait, a: Outer.NestedAnnotation) {
     ClassObject
 }

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>