Factor out duplicated mangling logic for functions into the base class

^KT-57777 Fixed
^KT-57818 Fixed

compiler/testData/ir/irText/classes/classes.kt

@@ -1,9 +1,6 @@
 // IGNORE_BACKEND: JS_IR
 // IGNORE_BACKEND: JS_IR_ES6
 
-// MUTE_SIGNATURE_COMPARISON_K2: ANY
-// ^ KT-57777
-
 class TestClass
 
 interface TestInterface

compiler/testData/ir/irText/classes/enum.kt

@@ -3,7 +3,7 @@
 // IGNORE_BACKEND: JS_IR_ES6
 
 // MUTE_SIGNATURE_COMPARISON_K2: ANY
-// ^ KT-57775, KT-57777
+// ^ KT-57775
 
 enum class TestEnum1 {
     TEST1, TEST2

compiler/testData/ir/irText/classes/enumClassModality.kt

@@ -2,7 +2,7 @@
 // IGNORE_BACKEND: JS_IR_ES6
 
 // MUTE_SIGNATURE_COMPARISON_K2: ANY
-// ^ KT-57775, KT-57777
+// ^ KT-57775
 
 enum class TestFinalEnum1 {
     X1

compiler/testData/ir/irText/classes/enumEntries.kt

@@ -3,9 +3,6 @@
 // FULL_JDK
 // WITH_STDLIB
 
-// MUTE_SIGNATURE_COMPARISON_K2: ANY
-// ^ KT-57775, KT-57430, KT-57777
-
 enum class MyEnum {
     Ok, Nope
 }

compiler/testData/ir/irText/classes/enumWithMultipleCtors.kt

@@ -2,7 +2,7 @@
 // IGNORE_BACKEND: JS_IR_ES6
 
 // MUTE_SIGNATURE_COMPARISON_K2: ANY
-// ^ KT-57775, KT-57777
+// ^ KT-57775
 
 enum class A {
     X("asd"),

compiler/testData/ir/irText/classes/enumWithSecondaryCtor.kt

@@ -3,7 +3,7 @@
 // IGNORE_BACKEND: JS_IR_ES6
 
 // MUTE_SIGNATURE_COMPARISON_K2: ANY
-// ^ KT-57775, KT-57777
+// ^ KT-57775
 
 enum class Test0(val x: Int) {
     ZERO;