Adds a flag onto InterceptorInfo to mark an interceptor's getter,
query, and enumerator callbacks as side-effect-free.

Bug: v8:7515
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Iafc5d2fa554d6d9a38604e179ea5b884c3b77af0
Reviewed-on: https://chromium-review.googlesource.com/957870
Commit-Queue: Erik Luo <luoe@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51969}