[11] RFR 8232051: Epsilon should warn about Xms/Xmx/AlwaysPreTouch configuration

[Aleksey Shipilev]

Original RFE:
  https://bugs.openjdk.java.net/browse/JDK-8232051
  https://hg.openjdk.java.net/jdk/jdk/rev/10db6989907f

Patch does not apply to 11u cleanly, because global package declaration in tests (JDK-8214799) is
not done in 11u. Only test is affected. 11u webrev:
  https://cr.openjdk.java.net/~shade/8232051/webrev.11u.01/

Testing: gc/epsilon {fastdebug,release}, adhoc tests

-- 
Thanks,
-Aleksey