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/smart/NoExtensionMethodFromClassObject.kt

@@ -0,0 +1,13 @@
+class X {
+    companion object {
+        fun String.f(): X = X()
+        fun g(): X = X()
+    }
+}
+
+fun foo(): X {
+    return <caret>
+}
+
+// ABSENT: f
+// EXIST: { lookupString:"g", itemText:"X.g", tailText:"() (<root>)" }