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

idea/testData/quickfix/insertDelegationCall/nonApplicableInsertThis.kt.after

@@ -0,0 +1,9 @@
+// "Insert 'this()' call" "true"
+
+open class B(val x: Int)
+
+class A : B {
+    constructor(x: String)<caret> : this()
+
+    constructor() : super(1)
+}