Fix visibility of protected classes in bytecode

Protected should be translated to public as in Java so that everything would
work at runtime. The real visibility is still saved to an InnerClasses
attribute

 #KT-8269 Fixed
 #KT-9246 Fixed
 #KT-10143 Fixed

compiler/testData/codegen/box/innerNested/protectedNestedClass.kt

@@ -0,0 +1,26 @@
+// See KT-9246 IllegalAccessError when trying to access protected nested class from parent class
+// TARGET_BACKEND: JVM
+// FILE: a.kt
+
+package a
+
+abstract class A {
+    protected class C {
+        fun result() = "OK"
+    }
+}
+
+// FILE: b.kt
+
+package b
+
+import a.A
+
+class B : A() {
+    protected val c = A.C()
+    val result: String get() = c.result()
+}
+
+fun box(): String {
+    return B().result
+}