RFR: 8311248: Refactor CodeCache::initialize_heaps to simplify adding new CodeCache segments [v9]

[Boris Ulasevich]

> These changes clean up the logic and the code of allocating codecache segments and add more testing of it, to open a door for further optimization of code cache segmentation.  The goal was to keep the behavior as close to the existing behavior as possible, even if it's not quite logical.
> 
> Also, these changes better account for alignment - PrintFlagsFinal shows the final aligned segment sizes, and the segments fill the ReservedCodeCacheSize without gaps caused by alignment.

Boris Ulasevich has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains ten additional commits since the last revision:

 - minor updates according to review comments
 - minor update: align_up for ReservedCodeCacheSize
 - one another cleanup round
 - minor update. removed helper function as it caused many comments in the review
 - set_size_of_unset_code_heap
 - minor update
 - apply suggestions
 - cleanup & test udpdate
 - 8311248: Refactor CodeCache::initialize_heaps to simplify adding new CodeCache segments

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17244/files
  - new: https://git.openjdk.org/jdk/pull/17244/files/d70aa718..b39dffdf

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17244&range=08
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17244&range=07-08

  Stats: 206276 lines in 4329 files changed: 71595 ins; 106446 del; 28235 mod
  Patch: https://git.openjdk.org/jdk/pull/17244.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17244/head:pull/17244

PR: https://git.openjdk.org/jdk/pull/17244