RFR(XS): 8229968: [TESTBUG] containers/docker/TestMemoryAwareness fails with -Xmx

[Nick Gasson]

Hi,

Please review this small change to one of the Docker tests:

Bug: https://bugs.openjdk.java.net/browse/JDK-8229968
Webrev: http://cr.openjdk.java.net/~ngasson/8229968/webrev.0/

The testOOM part of this test fails if jtreg is run with an -Xmx option
as this will override the ergonomic heap sizing. (E.g. `make test
JTREG="MAX_MEM=768m"`). Simple fix is to use the existing mechanism to
ignore java options from the test environment when starting the process
inside the container.

Thanks,
Nick