RFR: 8311248: Refactor CodeCache::initialize_heaps to simplify adding new CodeCache segments [v7]

[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 incrementally with one additional commit since the last revision:

  minor update. removed helper function as it caused many comments in the review

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17244/files
  - new: https://git.openjdk.org/jdk/pull/17244/files/b54bbd9a..29e78046

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17244&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17244&range=05-06

  Stats: 39 lines in 1 file changed: 11 ins; 26 del; 2 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