runtime: skip TestNoShrinkStackWhileParking on netbsd/arm64
runtime: skip TestNoShrinkStackWhileParking on netbsd/arm64

This test appears to deadlock frequently on the only netbsd-arm64
builder we have (netbsd-arm64-bsiegert). Skip the test to provide
more useful test coverage for other failures.

For #49382

Change-Id: I3be32f58ce1e396f7c69163e70cf58f779f57ac6
Reviewed-on: https://go-review.googlesource.com/c/go/+/361615
Trust: Bryan C. Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
Trust: Benny Siegert <05f4aee36fd25d0de2a07789fd6e73398db492cc@gmail.com>
Run-TryBot: Bryan C. Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
Reviewed-by: Benny Siegert <05f4aee36fd25d0de2a07789fd6e73398db492cc@gmail.com>

cloudflare/go,CAFxX/go,CAFxX/go,CAFxX/go,nawawi/go,golang/go,nawawi/go,cloudflare/go,cloudflare/go,CAFxX/go,cloudflare/go,golang/go,golang/go,nawawi/go,nawawi/go,CAFxX/go,golang/go,nawawi/go,golang/go,nawawi/go,CAFxX/go,cloudflare/go,cloudflare/go,CAFxX/go,golang/go,cloudflare/go,golang/go,CAFxX/go,nawawi/go,golang/go,cloudflare/go,nawawi/go