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

idea/testData/quickfix/changeSignature/addFunctionParameterLongNameRuntime.kt.after

@@ -0,0 +1,10 @@
+// "Add parameter to function 'foo'" "true"
+// DISABLE-ERRORS
+
+import java.util.LinkedHashSet
+
+fun foo(x: Int, linkedHashSet: LinkedHashSet<Int>) {
+    foo(, java.util.LinkedHashSet<Int>());
+    foo(1, java.util.LinkedHashSet<Int>());
+    foo(2, java.util.LinkedHashSet<Int>());
+}