Add file lock to serialize bazel_build.py builds.
Add file lock to serialize bazel_build.py builds.

This serializes not only the Bazel build invocations, but also the
Tulsi script actions to delete symlinks, clear temp files, remove
assumed expired dSYMs, and others to prevent accidentally parallel
behavior.

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PiperOrigin-RevId: 175993048
MOS_MIGRATED_REVID=175993048

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