Prohibit accessing nested classes/objects of class object using class literal

The fqname of class should be clear from code
Example: can't shorten A.Default.B.Default.C to A.B.C
Also fixes problem when nested class of enum class could be accessed via enum entry

idea/testData/completion/basic/common/NestedClassesOnClassWithDefaultObject.kt

@@ -0,0 +1,27 @@
+class A {
+    class Nested
+    inner class Inner
+
+    class object {
+        class Nested2
+        val c: Int = 1
+        object Obj2
+
+        fun foo() {
+        }
+    }
+
+    object Obj
+}
+
+fun some() {
+    A.<caret>
+}
+
+// EXIST: Nested
+// EXIST: Default
+// EXIST: c
+// EXIST: foo
+// EXIST: Obj
+// ABSENT: Nested2
+// ABSENT: Obj2

idea/testData/completion/basic/common/NestedClassesOnClassWithNamedDefaultObject.kt

@@ -0,0 +1,27 @@
+class A {
+    class Nested
+    inner class Inner
+
+    class object Named {
+        class Nested2
+        val c: Int = 1
+        object Obj2
+
+        fun foo() {
+        }
+    }
+
+    object Obj
+}
+
+fun some() {
+    A.<caret>
+}
+
+// EXIST: Nested
+// EXIST: Named
+// EXIST: c
+// EXIST: foo
+// EXIST: Obj
+// ABSENT: Nested2
+// ABSENT: Obj2

idea/testData/completion/basic/common/NestedClassesOnDefaultObjectLiteral.kt

@@ -0,0 +1,27 @@
+class A {
+    class Nested
+    inner class Inner
+
+    class object Named {
+        class Nested2
+        val c: Int = 1
+        object Obj2
+
+        fun foo() {
+        }
+    }
+
+    object Obj
+}
+
+fun some() {
+    A.Named.<caret>
+}
+
+// EXIST: Nested2
+// EXIST: c
+// EXIST: foo
+// EXIST: Obj2
+// ABSENT: Nested
+// ABSENT: Named
+// ABSENT: Obj

idea/testData/completion/handlers/ClassFromClassObject.kt

@@ -5,5 +5,5 @@ class Test {
 }
 
 fun test() {
-    Test.S<caret>
+    Test.Default.S<caret>
 }

idea/testData/completion/handlers/ClassFromClassObject.kt.after

@@ -5,5 +5,5 @@ class Test {
 }
 
 fun test() {
-    Test.Some<caret>
+    Test.Default.Some
 }

idea/testData/completion/handlers/ClassFromClassObjectInPackage.kt

@@ -7,5 +7,5 @@ class Test {
 }
 
 fun test() {
-    a.Test.S<caret>
+    a.Test.Default.S<caret>
 }

idea/testData/completion/handlers/ClassFromClassObjectInPackage.kt.after

@@ -7,5 +7,5 @@ class Test {
 }
 
 fun test() {
-    a.Test.Some<caret>
+    a.Test.Default.Some<caret>
 }