Prevent generation of delegations to interfaces private methods

#KT-13381 Fixed
 #KT-13996 Fixed

compiler/testData/codegen/bytecodeListing/noDelegationsToPrivateInterfaceMembers.kt

@@ -0,0 +1,10 @@
+interface A {
+    // There must be no delegation methods for 'log' and 'bar' in C as they are private
+    private val log: String get() = "O"
+    private fun bar() = "K"
+
+    fun foo() = log + bar()
+}
+
+interface B : A
+class C : B