Stage 3 proposal: https://github.com/tc39/proposal-class-static-block

Bug: v8:11375
Change-Id: I579adab4679cce0190b9d8bd814a7cd297ebfa15
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2699449Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72847}