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

idea/testData/quickfix/createFromUsage/createFunction/set/createSetFromUsage2.kt.after

@@ -0,0 +1,13 @@
+// "Create extension function 'set'" "true"
+
+import java.util.ArrayList
+
+class Foo<T> {
+    fun <T> x (y: Any, w: java.util.ArrayList<T>) {
+        y["", w] = w
+    }
+}
+
+fun <T> Any.set(s: String, w: ArrayList<T>, value: ArrayList<T>) {
+    throw UnsupportedOperationException("not implemented") //To change body of created functions use File | Settings | File Templates.
+}