Migrate macos jobs to macos_arm64

[ted-xie]

The Intel macos deployment in BazelCI does not have the latest Android build tools installed. By default, BazelCI adds ANDROID* environment variables to builds, which registers an Android toolchain for any transitively-loaded Android deps, which causes a repo rule-level error.

To prevent this, this PR migrates macos jobs to macos_arm64.

[ted-xie]

NOTE: An alternative is to change the BazelCI platform from macos to macos_arm64.

[hvadehra]

Why are we polluting rules repo configs if the issue is in how Bazel CI is configured/deployed? Surely we should instead just not set these vars in bazelci.py when the platform is macos?

[ted-xie]

I would argue that it's also not good to specialize BazelCI to do special behavior for just one platform-type due to technical limitations of the underlying system. WDYT about this instead:

NOTE: An alternative is to change the BazelCI platform from macos to macos_arm64.

AFAIK there's no real need for rules_testing to test on Intel Macs specifically, and the arm64 Macs in BazelCI are faster.

[ted-xie]

Changed the scope of this PR to migrate macos to macos_arm64, which is faster in BazelCI anyway.

[hvadehra]

Thanks. Do you know when you expect things to start failing without this change?

[ted-xie]

In 1-2 weeks, after I land bazelbuild/bazel#29854