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

idea/testData/quickfix/variables/removeValVarFromParameter/loopParameter.kt

@@ -0,0 +1,6 @@
+// "Remove 'val' from parameter" "true"
+fun f(list: List<String>) {
+    for (val<caret> x in list) {
+
+    }
+}