[infra] Decrease number of changed test results sent to results feed
[infra] Decrease number of changed test results sent to results feed

The cloud functions processing changed test results are timing out
when sent 100 changes to process at once, reduce chunk size to 50.

Fixes:https://github.com/dart-lang/dart_ci/issues/46
Change-Id: I2046475e586e6801a4dab5fa6e1686568c0ba17c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/195992
Auto-Submit: William Hesse <a821cddceae7dc400f272e3cb1a72f400f9fed6d@google.com>
Commit-Queue: Alexander Thomas <29642742b6693024c89de8232f2e2542cf7eedf7@google.com>
Reviewed-by: Alexander Thomas <29642742b6693024c89de8232f2e2542cf7eedf7@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk