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

idea/testData/quickfix/createFromUsage/createFunction/next/createNextFromUsage2.kt

@@ -0,0 +1,12 @@
+// "Create function 'next'" "true"
+class FooIterator<T> {
+    fun hasNext(): Boolean { return false }
+}
+class Foo<T> {
+    fun iterator(): FooIterator<T> {
+        throw Exception("not implemented")
+    }
+}
+fun foo() {
+    for (i: Int in Foo<caret><Int>()) { }
+}