[K/N][codegen] Refactored interface calls

Removed old impl for debug builds
Fixes https://youtrack.jetbrains.com/issue/KT-44547 as a side effect

kotlin-native/backend.native/tests/codegen/interfaceCallsNCasts/functionNameClash.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+package codegen.interfaceCallsNCasts.functionNameClash
+
+import kotlin.test.*
+
+interface I1<T> {
+    fun foo(x: T): String
+}
+interface I2<T> {
+    fun foo(x: T): String
+}
+class C : I1<String>, I2<Int> {
+    override fun foo(x: String) = "I1.foo($x)"
+    override fun foo(x: Int) = "I2.foo($x)"
+}
+
+@Test
+fun runTest() {
+    val c = C()
+    val i1: I1<String> = c
+    assertEquals("I1.foo(str)", i1.foo("str"))
+    val i2: I2<Int> = c
+    assertEquals("I2.foo(42)", i2.foo(42))
+}