RFR: 8281946: VM.native_memory should report size of shareable memory [v6]

[Matias Saavedra Silva]

> The native memory reporting has been improved to also include the amount of shareable (read only) data. Verified with test tiers 1,2, and 4.
> 
> Sample output:
> 
> Total: reserved=33890498670, committed=2360907886
>        malloc: 75159662 #26118
>        mmap:   reserved=33815339008, committed=2285748224
> .............
> -        Shared class space (reserved=16777216, committed=13545472, readonly=8315472)
>                             (mmap: reserved=16777216, committed=13545472) 
>  
> -               Arena Chunk (reserved=441792, committed=441792)
>                             (malloc=441792)

Matias Saavedra Silva has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 14 commits:

 - Merging with master
 - Reverted and ajusted test
 - Ioi comments
 - Comments and suggestions
 - Assert should now pass on windows
 - Fixed assert for windows platform
 - Moved filemap include below precompiled
 - Removed unused lines
 - Merge branch 'master' into nativeMemory_8281946
 - Merge branch 'master' into nativeMemory_8281946
 - ... and 4 more: https://git.openjdk.org/jdk/compare/ea83cb96...d6aa9ac2

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

Changes: https://git.openjdk.org/jdk/pull/11401/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11401&range=05
  Stats: 41 lines in 3 files changed: 31 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/11401.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11401/head:pull/11401

PR: https://git.openjdk.org/jdk/pull/11401