Big change in quickfix tests: no stupid test data format with "before" and "after" file prefixes

idea/testData/quickfix/createFromUsage/createFunction/get/createGetFromUsage3.kt

@@ -0,0 +1,6 @@
+// "Create function 'get'" "true"
+class Foo<T> {
+    fun <S> x (y: Foo<Iterable<S>>) {
+        val z: Iterable<S> = y<caret>[""]
+    }
+}