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

idea/testData/quickfix/override/nothingToOverride/swapParametersGenericClass.kt

@@ -0,0 +1,8 @@
+// "Change function signature to 'fun f(y: S, x: List<Set<R>>)'" "true"
+trait A<P,Q> {
+    fun f(a: Q, b: List<Set<P>>)
+}
+
+class B<R,S> : A<R,S> {
+    <caret>override fun f(x: List<Set<R>>, y: S) {}
+}