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

idea/testData/quickfix/createFromUsage/createVariable/property/topLevelValWithPackageName.kt.after

@@ -0,0 +1,10 @@
+// "Create property 'foo'" "true"
+// ERROR: Property must be initialized
+
+package foo
+
+val foo: Int
+
+fun test(): Int {
+    return foo
+}