Created module idea-test-framework and moved classes needed for idea tests there

Moved tests for completion and their test data into module idea-completion

idea/idea-completion/testData/basic/common/ExtendClassName.kt

@@ -0,0 +1,13 @@
+open class MySecondClass() {
+}
+
+open class MyFirstClass<T> {
+
+}
+
+class A() : My<caret> {
+    public fun test() {
+    }
+}
+
+// EXIST: MySecondClass, MyFirstClass