RFR: 8322255: Generational ZGC: ZPageSizeMedium should be set before MaxTenuringThreshold [v2]

[Guoxiong Li]

> Hi all,
> 
> This patch fixes several issues about heuristics.
> 
> 1. Move `ZHeuristics::set_medium_page_size` to `ZArguments::initialize` so that the setting of `MaxTenuringThreshold` can use `ZPageSizeMedium` correctly.
> 2. Fix `ZHeuristics::use_per_cpu_shared_small_pages` to meet its comment.
> 3. Fix `ZHeuristics::significant_heap_overhead` and `ZHeuristics::significant_young_overhead` to use `ZFragmentationLimit` and `ZYoungCompactionLimit` as percentages instead of multiples.
> 
> Thanks for the review.
> 
> Best Regards,
> -- Guoxiong

Guoxiong Li has updated the pull request incrementally with one additional commit since the last revision:

  Remove unrelated change.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17137/files
  - new: https://git.openjdk.org/jdk/pull/17137/files/d67fb457..5fe86a61

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17137&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17137&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/17137.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17137/head:pull/17137

PR: https://git.openjdk.org/jdk/pull/17137