RFR: 8301403: Eliminate memory allocations in JVMFlag::printFlags during signal handling [v11]

[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 incrementally with one additional commit since the last revision:

  need 32 bit version of LogBytesPerWord too

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20202/files
  - new: https://git.openjdk.org/jdk/pull/20202/files/6f91dd30..c0a230b5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20202&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20202&range=09-10

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 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