RFR: 8249676: [REDO] G1 incorrectly limiting young gen size when using the reserve can result in repeated full gcs [v2]

[Thomas Schatzl]

> Hi,
> 
>   please review this re-application of JDK-8249676. The change passes two tier8 (plus tier1-7 which never were a problem)
>   runs w/o problems; the crashes I reported in the original review are gone after recent (other) changes.
> 
> Note that this PR contains two commits: the vanilla original patch and an update to fix merge errors with the recent
> IHOP changes.
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev
excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since
the last revision:

 - kbarrett review
 - Merge issues resolved
 - Original patch

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/108/files
  - new: https://git.openjdk.java.net/jdk/pull/108/files/93d8ba46..ff64ae37

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=108&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=108&range=00-01

  Stats: 12581 lines in 335 files changed: 6679 ins; 4073 del; 1829 mod
  Patch: https://git.openjdk.java.net/jdk/pull/108.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/108/head:pull/108

PR: https://git.openjdk.java.net/jdk/pull/108