RFR(S): JDK-8196590 Enable docker container related tests for linux AARCH64

[Dmitry Samersoff]

Everybody,

Please review small changes, that enables docker testing on Linux/AArch64

http://cr.openjdk.java.net/~dsamersoff/JDK-8196590/webrev.01/

PS:

Matthias - I refactored VMProps.dockerSupport() a bit to make it more
readable, please check that it doesn't brake your work.

-Dmitry

--
Dmitry Samersoff
http://devnull.samersoff.net
* There will come soft rains ...