KT-43045 mangle function name for fake override with default impl

compiler/testData/codegen/bytecodeListing/inlineClasses/defaultInterfaceMethodsInInlineClass.kt

@@ -0,0 +1,9 @@
+interface IFoo<T> {
+    fun foo(x: T): String = "OK"
+    fun T.bar(): String = "OK"
+    fun withDefault(x: T, y: Int = 42): String = "OK"
+}
+
+inline class L(val x: Long) : IFoo<L>
+
+class X : IFoo<L>