Run Bazel test suite on Linux ARM64 platform

skycache: don't try to get cache hits for SourceArtifacts by returning earlier than the SkyValueRetriever call.

Failed in 1m 19s
:ubuntu: Ubuntu 20.04 LTS ARM64curl -sS https://raw.githubusercontent.com/bazelbuild/continuous-integration/master/buildkite/bazelci.py?1739369681 -o bazelci.py && python3.8 bazelci.py runner --task=ubuntu2004_arm64 --http_config=https://raw.githubusercontent.com/bazelbuild/continuous-integration/master/pipelines/bazel-linux-arm64.yml?1739369680
Waited 3s
·
Ran in 40s
Total Job Run Time: 1m 17s