test: http2-respond-file-range to use fixtures

Changed test-http2-respond-file-range to use fixtures.path directly
instead of passing through the common module.

PR-URL: https://github.com/nodejs/node/pull/15852


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ryan Graham <r.m.graham@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>