RFR (S): 8145534: TestRemsetLogging.java takes a long time

[Thomas Schatzl]

Hi all,

  can I have reviews for the following changes to gc/g1/TestRemset*
tests that decrease its runtime significantly?

Most of the runtime improvements come from using WhiteBox methods to
start gcs (instead of allocating objects and waiting for it to happen),
then forcing that test to use the interpreter (because starting up the
compilers only slows it down), and some measures to improve startup.

In total all this decreases fastdebug VM runtime from 100s to 17s on my
local machine.

The changes also add @requires tags and deletes equivalent java code.

CR:
https://bugs.openjdk.java.net/browse/JDK-8145534
Webrev:
http://cr.openjdk.java.net/~tschatzl/8145534/webrev/
Testing:
looking at run times of jprt jobs which are much better now. There is
still some variation, but they are in the same range as other tests now.

Thanks,
  Thomas