Revert of V8: increase number of shards for arm64 gc stress. (patchset #1 id:1 of https://codereview.chromium.org/2248363003/ )

Reason for revert:
The root cause of the slow tests has been fixed. A shard increase is not needed.

Original issue's description:
> V8: increase number of shards for arm64 gc stress.
>
> Reason: shard#0 is timing out on swarming.
> Expected follow up: if this helps, shard in other
> builders as well.
>
> R=hablich@chromium.org
> CC=machenbach@chromium.org
> BUG=638295
>
> Committed: https://chromium.googlesource.com/chromium/tools/build/+/a415f195afcd9db6c89a5da50df939e76d69b849

TBR=hablich@chromium.org,tandrii@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=638295

Review-Url: https://codereview.chromium.org/2291703003
2 files changed