RFR: 8357086: os::xxx functions returning memory size should return size_t [v13]

[Anton Artemov]

> Hi,
> 
> in this PR the output value types for functions which return memory are changed, namely:
> 
> 
> static julong available_memory(); --> static bool available_memory(size_t& value);
> static julong used_memory(); --> static bool used_memory(size_t& value);
> static julong free_memory(); --> static bool free_memory(size_t& value); 
> static jlong total_swap_space(); --> static bool total_swap_space(size_t& value);
> static jlong free_swap_space(); --> static bool free_swap_space(size_t& value); 
> static julong physical_memory(); --> static bool physical_memory(size_t& value); 
> 
> 
> The return boolean value indicates success, whereas the actual value is assigned to the input argument. The following recommended usage pattern is introduced: where applicable, and unsuccessful call is logged. 
> 
> Later, the return value can be attributed with `[[nodiscard]]` to enforce the pattern.
> 
> Tested in GHA and Tiers 1-5.

Anton Artemov has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 12 commits:

 - 8357086: Fxied return value
 - 8357086: Fixed whitespaces
 - 8357086: Introduced usage pattern
 - 8357086: Fixed typo
 - 8357086: Refactored physical_memory in different OS
 - 8357086: Small fixes 2
 - 8357086: Small fixes 1.
 - 8357086: Refactored physical_memory()
 - 8357086: Refactored free_swap_space()
 - 8357086: Refactored total_swap_space()
 - ... and 2 more: https://git.openjdk.org/jdk/compare/75ce44aa...e4698333

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Changes: https://git.openjdk.org/jdk/pull/25450/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25450&range=12
  Stats: 325 lines in 22 files changed: 164 ins; 2 del; 159 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