Run terminateTestProcesses before git clone

We do `forceCleanWS()` before git clone to ensure a clean workspace.
https://github.com/adoptium/aqa-tests/blob/master/buildenv/jenkins/openjdk_tests#L457

We have noticed on Windows (maybe z/OS as well), if the previous job exited not cleanly (i.e., Jenkins restarted) and left a running Java process holding the folder, the next job that lands on the machine cannot run cleanWs. When this happens, the job will fail and the machine will be marked offline automatically.

I think we should do a little more - try to kill the level over processes. It means to run [terminateTestProcesses.sh](https://github.com/adoptium/aqa-tests/blob/master/terminateTestProcesses.sh) to terminate any left over processes before the first `forceCleanWS()`. Because the repo is not cloned yet at this time, we need to download the script alone/separately and run it before forceCleanWS().

Start at buildenv/jenkins/openjdk_tests around line 457 and inspect terminateTestProcesses.sh. Determine how to obtain and run that script before the first forceCleanWS(), before the repository is cloned. Done means leftover processes are terminated before cleanup is attempted.

Written by the indexing model from the issue text.