A new class of build node has recently been added which appears to have fewer
memory resources than previous nodes, causing integration test failures. The
gradle task for integration tests doesn't appear to require 4gb, so this commit
reduces the -Xmx setting to 4gb
This commit includes:
* A base Dockerfile and script to push to a Docker repo
* A per-build Dockerfile (derived from the base)
* Updates to the test scripts to allow for more parallel builds
* Docker wrappers for the tests scripts
* Update for the integration test readme to manually run the tests
* Clean up the output of the Java tests
* Remove offline tag for tests (no longer needed that we don't use docker dependent services)
This commit does NOT include:
* Changes needed for the CI system to use Docker
Fixes#8223
