RFR: 8285094: Test java/awt/Frame/InvisibleOwner/InvisibleOwner.java failing on Linux [v3]

[Phil Race]

> As discussed in https://bugs.openjdk.java.net/browse/JDK-8285094 it seems that the test
> java/awt/Frame/GetGraphicsStressTest/GetGraphicsStressTest.java destabilises the Xserver.
> This causes java/awt/Frame/InvisibleOwner/InvisibleOwner.java to fail and even before that
> other tests which do  pass are not visibly behaving as expected.
> 
> I didn't find any Xserver logs of "bad stuff" happening so it just seems like the Xserver was
> having trouble keeping up and JDK was behaving correctly as it could despite the Xserver sending
> lots of requests to repaint.
> 
> Just the "sleep" at the end of GetGraphicsStressTest.java seems to be enough but I'd already
> reworked InvisibleOwner.java and I'd like to think it is a bit better than before.

Phil Race has updated the pull request incrementally with one additional commit since the last revision:

  8285094

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8312/files
  - new: https://git.openjdk.java.net/jdk/pull/8312/files/160b4eae..915e6aea

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8312&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8312&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8312.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8312/head:pull/8312

PR: https://git.openjdk.java.net/jdk/pull/8312