RFR: 8293218: serviceability/tmtools/jstat/GcNewTest.java fails with "Error in the percent calculation"

[Kevin Walls]

Test update to cope with heap size changing (shrinking) in the early life of the test app.

A change in GC timing affects this test which reads eden size and heap size.  Both eden and heap are likely to shrink initially for this test.  Failures were that heap size shrank after reading eden size, such that eden appeared to be >100% of heap.
Recognising a shrinking heap and retrying resolves this.  

(Re-ordering to read heap size then eden would be enough to make the check in provokeGc work.  But it would allocate sometimes a very small fraction of the heap, which is not the intent.)

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Commit messages:
 - comment
 - un-problemlist
 - Merge branch 'master' into 8293218_GcNewTest
 - 8293218: serviceability/tmtools/jstat/GcNewTest.java fails with "Error in the percent calculation"

Changes: https://git.openjdk.org/jdk/pull/10218/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10218&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293218
  Stats: 21 lines in 2 files changed: 12 ins; 1 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/10218.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10218/head:pull/10218

PR: https://git.openjdk.org/jdk/pull/10218