This commit teaches the build how to bundle AdoptOpenJDK with our
artifacts, and switches to AdoptOpenJDK as the bundled JDK. We keep the
functionality to also bundle Oracle OpenJDK distributions.
Testclusters currently provides protection from clusters living past the
life of a build by adding a shutdown hook to java. While this works in
some cases, it does not cover all cases like where the daemon is killed
with SIGKILL.
To handle these other cases, this commit replaces the shutdown hooks with
a separate process (one per build) that manages reaping external services
if gradle dies.
Mark Vieira
Jason Tedor
Ryan Ernst