Don't normalize whitespace in fourslash tests (#18447)

* Don't normalize whitespace in fourslash tests

* Only render whitespace when the diff is text-only

src/server/protocol.ts

@@ -494,6 +494,7 @@ namespace ts.server.protocol {
         refactor: string;
         /* The 'name' property from the refactoring action */
         action: string;
+        formatOptions: FormatCodeSettings,
     };