RFR: 8260349: Cannot programmatically retrieve Metaspace max set via JAVA_TOOL_OPTIONS [v4]

[David Holmes]

> A simple but long standing bug whereby the MemoryPool MXBean only sees the value of MaxMetaspaceSize if it was set directly on the command-line and not by other means (e.g. env var).
> 
> Fix is to check !FLAG_IS_DEFAULT rather than FLAG_IS_CMDLINE.
> 
> Expanded regression test added (based on the reproducer in the JBS issue) that checks all the ways to set the flag: cmd-line, env-var, hotspotrc file
> 
> Testing: regression test (before and after fix)
>              tiers 1-3 (in progress)
> 
> Thanks,
> David

David Holmes 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 seven additional commits since the last revision:

 - Further formatting updates from Aleksey
 - Merge branch 'master' into 8260349
 - Cleaned up test formatting based on Aleksey's review
 - Added missing test case for flag not set
 - Boost max from 1MB to 9MB as 1MB was too low for Aarch64 to startup
 - Reduced test code using loop for env-vars
 - 8260349: Cannot programmatically retrieve Metaspace max set via JAVA_TOOLS_OPTIONS

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2275/files
  - new: https://git.openjdk.java.net/jdk/pull/2275/files/a21b75be..2c3cad6b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2275&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2275&range=02-03

  Stats: 5779 lines in 137 files changed: 4507 ins; 724 del; 548 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2275.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2275/head:pull/2275

PR: https://git.openjdk.java.net/jdk/pull/2275