Fixes a potential overflow when using the runtime's StringCompareSequence
by checking the string length first.

Bug: chromium:1032906
Change-Id: I7cb94473ae8331dd2ecf1fa98034829bebf8a9ac
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1973936
Commit-Queue: Joshua Litt <joshualitt@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65558}