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

idea/testData/quickfix/createFromUsage/createVariable/property/memberVarDelegateRuntime.kt

@@ -0,0 +1,7 @@
+// "Create property 'foo'" "true"
+// ERROR: Property must be initialized or be abstract
+// ERROR: Variable 'foo' must be initialized
+
+class A<T> {
+    var x: A<Int> by <caret>foo
+}