The matrix variables were left over from copy/pasting the contents
of the normal CI workflow. We also should always skip saving the
cache, as the normal CI pipeliens will refresh the toolchain and
we should just be reading the cache.
The cache is saving, but by the time we run again, it looks like the
cache has been purged from other jobs consuming the cache.
This causes the cache to fail restore. Given we run nightly and there
is no time bound, we can just run without cache.
Test files were getting analyzed twice, which the tool does
not like, and causes it to exit with a fatal error.
Also make the workflow run in PRs anytime the file is edited,
so that we can get immediate feedback without waiting till the
next day.
This action executes once a day, the sonar cloud runner analyzes the
code and then uploads the results.
The current code base takes almost 3 hours of computer time to analyze.
The runner supports multi threaded executing and caching of results, so
we save that cache as part of the github action work flow to allow for
the analysis to skip unchanged files.
