RFR: 8269914: Factor out heap printing for G1 young and full gc [v3]

[Thomas Schatzl]

> Hi all,
> 
> can I have reviews for this change that factors out before/after heap related printing into a single scoped object to be used for both young and full gc code?
> 
> There is some minor change in order of printing of unrelated log output (COMMIT/UNCOMMIT region state changes vs. other heap printing), during full gc but since this is very low level debugging I do not see a problem to do that.
> 
> (Sorry for the trouble with open/closing this issue already: have been experimenting with the feature to base PRs on other PRs which kind-of failed a bit; rebased on tip after being able to push all dependencies, so this one should be good)
> 
> To keep JFR event sending in the correct order, this change includes JDK-8270018.
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:

  ayang review

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4705/files
  - new: https://git.openjdk.java.net/jdk/pull/4705/files/b5b57c06..f0506932

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4705&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4705&range=01-02

  Stats: 28 lines in 5 files changed: 2 ins; 3 del; 23 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4705.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4705/head:pull/4705

PR: https://git.openjdk.java.net/jdk/pull/4705