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

idea/testData/quickfix/createFromUsage/createVariable/parameter/assignedInFun.kt

@@ -0,0 +1,8 @@
+// "Create parameter 'foo'" "false"
+// ACTION: Create local variable 'foo'
+// ACTION: Create property 'foo'
+// ERROR: Unresolved reference: foo
+
+fun test(n: Int) {
+    <caret>foo = n + 1
+}