RFR: 8357086: os::xxx functions returning memory size should return size_t [v5]

[Anton Artemov]

> Hi,
> 
> in this PR the output value type for functions which return memory are changed, namely:
> 
> 
> static julong available_memory(); --> static size_t available_memory();
> static julong used_memory(); --> static size_t used_memory();
> static julong free_memory(); --> static size_t free_memory(); 
> static jlong total_swap_space(); --> static ptrdiff_t total_swap_space();
> static jlong free_swap_space(); --> static ptrdiff_t free_swap_space(); 
> static julong physical_memory(); --> static size_t physical_memory(); 
> 
> 
> The changes are done so that the other parts of the code have minimal impact. 
> Tested in GHA and Tiers 1-4.

Anton Artemov 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 12 additional commits since the last revision:

 - Merge remote-tracking branch 'origin/master' into JDK-8357086_size_t_memfuncs
 - 8357086: Fixed spaces in formatting in gc-related code.
 - 8357086: Fixed formatting.
 - 8357086: Addressed reviewer's comments.
 - 8357086: More work.
 - 8357086: More work.
 - 8357086: More work.
 - 8357086: More work.
 - 8357086: More work.
 - 8357086: More work
 - ... and 2 more: https://git.openjdk.org/jdk/compare/f7c8a5a9...f3a5f61c

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25450/files
  - new: https://git.openjdk.org/jdk/pull/25450/files/f8a9d608..f3a5f61c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25450&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25450&range=03-04

  Stats: 87128 lines in 1504 files changed: 53638 ins; 21091 del; 12399 mod
  Patch: https://git.openjdk.org/jdk/pull/25450.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25450/head:pull/25450

PR: https://git.openjdk.org/jdk/pull/25450