interpret class in class object as static nested class

removed hack in TaskPrioritizer for import class from class object

idea/testData/editor/optimizeImports/Kt2709.kt

@@ -6,6 +6,6 @@ fun main() {
 
 class MyClass {
     class object {
-        public val TEST: String = ""
+        object TEST {}
     }
 }

idea/testData/editor/optimizeImports/Kt2709_after.kt

@@ -6,6 +6,6 @@ fun main() {
 
 class MyClass {
     class object {
-        public val TEST: String = ""
+        object TEST {}
     }
 }