Moves the unicode predicate cache tables out of the unicode cache,
and turns them into generic predicates in char-predicates.h which
use static constexpr tables.

This drops the per-isolate cost of unicode caches, and removes the
need for accessing the unicode cache from most files. It does remove
the mutability of the cache, which means that there may be regressions
when parsing non-ASCII identifiers. Most likely the benefits to ASCII
identifiers/keywords will outweigh any non-ASCII costs.

Change-Id: I9a7a8b7c9b22d3e9ede824ab4e27f133ce20a399
Reviewed-on: https://chromium-review.googlesource.com/c/1335564Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57506}