test: remove unneeded --expose-internals

test/wpt/test-timers.js does not appear to need the `--expose-internals`
flag. Remove it.

PR-URL: #27608
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Yongsheng Zhang <[email protected]>
Reviewed-By: Richard Lau <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>

Author: Trott

test/wpt/test-timers.js

@@ -1,7 +1,5 @@
 'use strict';
 
-// Flags: --expose-internals
-
 require('../common');
 const { WPTRunner } = require('../common/wpt');