Introduction of CastedClassReceiver and its handling in codegen #KT-6744 Fixed

ClassReceiver converted to Kotlin
Also #KT-7617 Fixed

compiler/testData/codegen/box/smartCasts/implicitToGrandSon.kt

@@ -0,0 +1,13 @@
+open class A {
+    open fun foo() = "FAIL"
+
+    fun bar() = if (this is C) foo() else foo()
+}
+
+open class B : A()
+
+open class C : B() {
+    override fun foo() = "OK"
+}
+
+fun box() = C().bar()