The class declaration regexp in cpplint did not catch classes decorated
by V8_EXPORT, V8_EXPORT_PRIVATE or any other decorator containing
digits.
This will be fixed in https://github.com/google/styleguide/pull/422.
This CL already prepares the code base by fixing all errors that will
be found after that change.
Some follow-up changes were needed to fix implicit conversion that are
not taken any more now.

R=mstarzinger@chromium.org

Bug: v8:8562
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I03713bd04dbc3f54b89a6c857a93463139aa5efd
Reviewed-on: https://chromium-review.googlesource.com/c/1367751Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58143}