Fix #4255: Double number of shards available for app tests

[BenHenning]

Explanation

Fixes #4255

App module tests are still running into memory issues (specifically shards 2 & 3). This change doubles the number of shards available so that hopefully the tests are better distributes and have a smaller chance of hitting memory limitations.

Essential Checklist

• The PR title and explanation each start with "Fix #bugnum: " (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• Any changes to scripts/assets files have their rationale included in the PR explanation.
• The PR follows the style guide.
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For UI-specific PRs only

N/A -- This is an infrastructure change that doesn't affect app behavior.

[BenHenning]

@anandwana001 PTAL when you get a chance (this isn't urgent, but it'll be nice to get in since I have to occasionally restart CI workflows at the moment).

[anandwana001]

LGTM

[oppiabot]

Hi @BenHenning, this PR is ready to be merged. Please address any remaining comments prior to merging, and feel free to merge this PR once the CI checks pass and you're happy with it. Thanks!

[BenHenning]

Ah, I apparently didn't do this correctly since the latest CI only ran 4. I suspect that I need to change something in the workflow, too.

[BenHenning]

Ah there we go. Needed to make sure all of the new shards are being run (otherwise it's more or less cutting the app module tests in half).

[BenHenning]

Welp looks like the same problem (exit code 134) happens even with 8 shards. It seems that this happened with StateFragmentLocalTest, so I'm wondering if we'll need to separate out the two state fragment tests into their own special shard since they clearly use far too many resources to be shared with a bunch of other app module tests.

That being said, I'm going to restart the workflow for this PR and try to merge it since 8 shards is still better than 4 for restarting, and hopefully lowers the chance of the Gradle tests failing.