When running in single-process mode for Webview, the stack limit is
initialized from a point closer to the top of stack limit. This causes
can cause crashes since the stack limit might be higher than the actual
native stack limit (which is 1MB on Android). As such, use the same
slightly lower stack limit on Arm64 as we do on Arm to give more slack.

BUG=v8:10575

Change-Id: I0cdd0cb4b38aafcb4e158ed639ecf3bba2edb785
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2250241
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Auto-Submit: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68405}