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/GenericKotlinClass.kt

@@ -0,0 +1,8 @@
+class Generic1<T>
+
+class Generic2<T1, T2>
+
+fun foo(): G<caret>
+
+// EXIST: { lookupString: "Generic1", itemText: "Generic1", tailText: "<T> (<root>)" }
+// EXIST: { lookupString: "Generic2", itemText: "Generic2", tailText: "<T1, T2> (<root>)" }