RFR: 8311248: Refactor CodeCache::initialize_heaps to simplify adding new CodeCache segments [v4]

[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 refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  apply suggestions

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17244/files
  - new: https://git.openjdk.org/jdk/pull/17244/files/06907581..9bd9da95

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17244&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17244&range=02-03

  Stats: 12 lines in 1 file changed: 6 ins; 6 del; 0 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