RFR: 8306440: Rename PSS:_num_optional_regions to _max_num_optional_regions [v3]

[Thomas Schatzl]

> Hi all,
> 
>    please review this small change that clarifies the use of `PSS::_num_optional_regions` to be the initial amount of optional regions, not the current amount of optional regions.
> 
> Testing: gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:

 - ayang review
 - Rename PSS:_num_optional_regions to _num_initial_optional_regions to emphasize that it's the initial amount of optional regions
   
   Rename the stated member to better indicate that this is the initial amount of optional
   region at the start of gc vs. the one for the current iteration of the evacuation.
   Optional.

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Changes: https://git.openjdk.org/jdk/pull/13532/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13532&range=02
  Stats: 10 lines in 3 files changed: 1 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/13532.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13532/head:pull/13532

PR: https://git.openjdk.org/jdk/pull/13532