Fix "Cannot infer visibility" for fake overrides

#KT-4785 Fixed

compiler/testData/diagnostics/tests/override/kt4785.kt

@@ -0,0 +1,11 @@
+trait T {
+    internal fun foo()
+}
+
+open class C {
+    protected fun foo() {}
+}
+
+class <!CANNOT_INFER_VISIBILITY!>E<!> : C(), T
+
+val z: T = <!CANNOT_INFER_VISIBILITY!>object<!> : C(), T {}

compiler/testData/diagnostics/tests/override/kt4785classObject.kt

@@ -0,0 +1,13 @@
+trait A {
+    internal fun foo()
+}
+
+trait B {
+    protected fun foo() {}
+}
+
+class C {
+    class <!CANNOT_INFER_VISIBILITY!>object<!> : A, B {
+        fun bar() = null
+    }
+}