RFR: 8301403: Eliminate memory allocations in JVMFlag::printFlags during signal handling [v7]

[Gerard Ziemski]

> Allocating memory while handling an error should be avoided, however `JVMFlag::printFlags()` is used by crash log and it allocates memory to print flags sorted (using qsort).
> 
> We avoid memory allocation by using a simple in place algorithm that uses JVMFlag 1 bit of unused data from its private `Flags` enum data member. It is O(n^2) algorithm, compared to O(n*log(n)) for qsort, however, it's called while handling an error log, so the speed here is not paramount. Also, I measured the real impact on a simple test case and I actually observed performance improvement of about x2.5 faster (2,885,973ns in place ordered printing vs 7,389,456ns for qsort). This is because we ended up having to qsort all flags when only a fraction of them actually end up being printed.
> 
> Running MACH5 tests...

Gerard Ziemski 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 eight additional commits since the last revision:

 - Merge remote-tracking branch 'upstream/master' into JDK-8301403
 - move include
 - use local stack storage for the sorting indicies
 - can not use new
 - switch to CHeapBitMap
 - remove unused header
 - change name from max to best
 - do not presort to avoid memory allocation

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20202/files
  - new: https://git.openjdk.org/jdk/pull/20202/files/1954fa89..20444667

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20202&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20202&range=05-06

  Stats: 12922 lines in 368 files changed: 9114 ins; 2112 del; 1696 mod
  Patch: https://git.openjdk.org/jdk/pull/20202.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20202/head:pull/20202

PR: https://git.openjdk.org/jdk/pull/20202