RFR: 8319630: Monitor final audit log lacks separator

[Stefan Karlsson]

There's a couple of problems with the "final audit" output for `is_busy` monitors.

1) The contentions field lacks a ", " when `contentions()` returns 0
2) The owner field lacks a ", " when owner is non-null

Example output before the patch:

[20.122s][info][monitorinflation] 0x0000600003fb4010 100 0x0000080000200908 java.lang.ref.NativeReferenceQueue$Lock (is_busy: waiters=1, contentions=0owner=0x0000000000000000, cxq=0x0000000000000000, EntryList=0x0000000000000000)
``` 

Tested with manual inspection. I couldn't find a pre-existing test for this output, so my guess is that it's mainly for HotSpot developers?

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Commit messages:
 - 8319630: Monitor final audit log lacks separator

Changes: https://git.openjdk.org/jdk/pull/16541/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16541&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319630
  Stats: 14 lines in 1 file changed: 0 ins; 1 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/16541.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16541/head:pull/16541

PR: https://git.openjdk.org/jdk/pull/16541