RFR: 8270014: Add scoped objects for g1 young gc verification and young gc internal timing [v4]

[Thomas Schatzl]

> Hi all,
> 
>   can I get reviews for some further cleanup of the young collection code:
> - adding some more scoped objects (verification, gc pause timing)
> - some naming, minor related code movement
> 
> Thanks,
>   Thomas

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

  Change note_ to record_

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4768/files
  - new: https://git.openjdk.java.net/jdk/pull/4768/files/b9b53f8d..b6be6fc5

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4768&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4768&range=02-03

  Stats: 10 lines in 3 files changed: 0 ins; 0 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4768.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4768/head:pull/4768

PR: https://git.openjdk.java.net/jdk/pull/4768