The shared scons cache is only written to on non-patch builds. Since commit queue builds have a high likelihood of being merged into master, it would be valuable to have them write to the cache as well. In particular, the next item in the commit queue could reuse a lot of the artifacts.

As a server engineer,
I want commit queue builds to write to the shared scons cache,
So that future commit queue builds can reuse the artifacts.

AC:

• Build done as part of the commit queue are able to write to the shared scons cache.

  ---

  The logic for whether the commit queue is read-only or read/write can be found here.

Additionally an expansion was added to tell if a given build is a commit queue build here.