Fix tests on non us-EN local env (#185)

* Fix tests on non us-EN local env

Different locale might result in different alphabetical order of tests in report. Tests using snapshot comparison then fails

* Fix code style

src/utils/node-utils.ts

@@ -1,5 +1,7 @@
 import {normalizeFilePath} from './path-utils'
 
+export const DEFAULT_LOCALE = 'en-US'
+
 export function getExceptionSource(
   stackTrace: string,
   trackedFiles: string[],