[8u] RFR: 8221710: [TESTBUG] more configurable parameters for docker testing

[Severin Gehwolf]

Hi,

Please review this backport for OpenJDK 8u. It's also been backported
by Oracle (I see 8u281). Besides, it makes testing container patches
easier as it allows one to specify some diagnostics/commands via
properties. It's also a pre-requisite for follow up patches I'd like to
bring to 8u: JDK-8227642 and JDK-8228434. The JDK 11 patch didn't apply
cleanly due to:

 * hotspot/jdk repositories being split in 8u
 * SkippedException not being present in 8u
 * Some context difference in DockerBasicTest.java ("jdk8-
   internal:test" which is different in 11u)

I've manually resolved the issues which was pretty straight-forward.

Bug: https://bugs.openjdk.java.net/browse/JDK-8221710
webrev: https://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8221710/jdk8/02/

Testing: Container tests on Linux x86_64 (cgroup v1).

Thoughts?

Thanks,
Severin