IC Mangling: search parents for method if descriptor is fake override

Otherwise, the compiler generates call using old mangling scheme
because classfile does not contain the method.

compiler/testData/compileKotlinAgainstKotlin/inlineClassFakeOverrideMangling.kt

@@ -0,0 +1,22 @@
+// !LANGUAGE: +InlineClasses
+
+// FILE: 1.kt
+
+inline class IC(val s: String)
+
+abstract class A {
+    fun foo(s: String) = IC(s)
+}
+
+open class C : A()
+
+class D: C()
+
+// FILE: 2.kt
+
+fun box(): String {
+    var res = C().foo("OK").s
+    if (res != "OK") return "FAIL 1 $res"
+    res = D().foo("OK").s
+    return res
+}