Fix asserts related to writing nameless parameters in HLSL We rely on TSymbol::name() to generate names also for nameless parameters. Fix asserts to reflect this. BUG=chromium:823041 TEST=angle_unittests Change-Id: Ie9b8253a150e79965bf85d8a7f36643ada6c54cc Reviewed-on: https://chromium-review.googlesource.com/968242 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>