'#x in expr' currently parses incorrectly and associates #x as an
operand of an existing binary expression continuation if the previous
operator was of higher precedence. For example, 0 << #x in foo gets
incorrectly parsed as (0 << #x) in foo.

Bug: v8:12259, v8:12086
Change-Id: Ie37ff49ff6e63b3ea91fd0fba6bc73ec839c580b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3176506Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77020}