These flags are suggested by GitHub support to disable reusing caches
during Gradle build. They think that could fix the intermittent error
message:
```
Encountered a fatal error while running "/opt/hostedtoolcache/CodeQL/2.19.0/x64/codeql/codeql database finalize --finalize-dataset --threads=4 --ram=14576 --verbosity=progress++ /home/runner/work/_temp/codeql_databases/java". Exit code was 32 and last log line was: CodeQL detected code written in Java/Kotlin but could not process any of it. For more information, review our troubleshooting guide at https://gh.io/troubleshooting-code-scanning/no-source-code-seen-during-build . See the logs for more details.
```
This fails for me every day for some reason (starting about a month
ago). The same commit went through the workflow fine when the action was
triggered by a push.
I think there's no reason for us to have a cron run as the changes to the
master branch can only come from commit pushes.
* Add a GitHub Action workflow
This allows us to create Gradle depedency graphs for Dependabot analysis (as the ones we already get for Javascript dependencies).
* Update Java version
* Add build scan
* codeql 3
* run with gradle
* exclude jIFC
* build scan
* Finalize
Make the necessary changes for the code base to compile with JDK 21.
Other changes:
1. Upgraded testcontainer version and the SQL image version (to be the
same as what we use in Cloud SQL). This led to some schema changes and
also changed the order of results in some test queries (for the
better I think, as the new order appears to be alphabetical).
2. Remove dependency on Truth8, which is deprecated.
3. Enable parallel Gradle task execution and greatly increased the
number of parallel tests in standardTest. Removed outcastTest.
