- Introduce Token::IsLiteral helper
- Introduce Token::IsStrictReservedWord helper


Drive-by-fix:
- Use "token" instead of "tok" as variable name
- Keep enum order consistent accross files

Change-Id: Ie3b30a62dfbea761a31c32465c0afa681d326710
Reviewed-on: https://chromium-review.googlesource.com/1203952Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55804}