These two tests fail if the memory used by builtins increases too much.
They aren't intended to monitor the memory used by builtins, so these
failures are spurious.

Bug: v8:8521
Change-Id: I67e61abe30aaf69aeb3e6a2c885795061a318851
Reviewed-on: https://chromium-review.googlesource.com/c/1354041
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57911}