internal/coordinator/pool: add GCP t2a instance quotas
internal/coordinator/pool: add GCP t2a instance quotas

This adds the ability to track quota for t2a instances which have an
ARM64 architecture. This is required functionality if the coordinator
makes use of this machine type.

Updates golang/go#53851

Change-Id: I5fd384fee78bd1817fb022e67ecaa3e405977e3b
Reviewed-on: https://go-review.googlesource.com/c/build/+/447260
Run-TryBot: Carlos Amedee <ab5e2bca84933118bbc9d48ffaccce3bac4eeb64@golang.org>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>
Reviewed-by: Carlos Amedee <ab5e2bca84933118bbc9d48ffaccce3bac4eeb64@golang.org>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

golang/build,golang/build,golang/build,golang/build