Add a persistent bazel server between builds

This feature is toggled on with USE_PERSISTENT_BAZEL, which is off by
default. Those that opt-in will have a bazel server running between
builds (with a 3hr default TTL) which will greatly improve analysis on
subsequent builds. (As Bazel maintains a cache of analysis results).

Bug: 266983462
Test: Manual `m nothing` runs (timing with and without the feature)
Test: New integration test
Test: Presubmits
Change-Id: I3af4948baa0c490e9b87c48ffdbe9f67732586c7