RFR: 8291037: Move PLAB resizing mechanism to G1EvacStats [v2]

[Thomas Schatzl]

> Hi all,
> 
>   please review this refactoring that moves the PLAB resizing mechanism to `G1EvacStats` as G1 is the only user for this functionality.
> 
> The change is split into two commits for easier review: 65eef6482cc0a995d29e822c9c26063bb42c7679 only moves the code,  028e3adeca1d496520f0c79f3b4bcedd7e7f0f15 tries to improve it a bit. 
> 
> Note that this change also removes the old, unused PLAB re-sizing algorithm previously used by CMS, hence the relatively large count of deleted LOC.
> 
> Testing: gha, gc/g1
> 
> Thanks,
>   Thomas

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

  improve one comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9644/files
  - new: https://git.openjdk.org/jdk/pull/9644/files/028e3ade..0f8bc696

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9644&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9644&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9644.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9644/head:pull/9644

PR: https://git.openjdk.org/jdk/pull/9644