RFR: 8377347: jdk/jfr/event/gc/detailed/TestZAllocationStallEvent.java intermittent OOME [v2]

[SendaoYan]

> Hi all,
> 
> Test test/jdk/jdk/jfr/event/gc/detailed/TestZAllocationStallEvent.java intermittent throw OOME on some specific mahcines. If I catch the OOM error wrapper the memory allocation loop, the Events.fromRecording still report OOM error. 
> The max memory heap was seted to 32M, this seems too small for ZGC to workly normally on some specific machines, The gc log shows that ZGC unable to recliam the heap memory.
> 
> This PR change  include:
> 
> 1. the -Xmx seted to 64G
> 2. increase the memory allocation loop count from 100 to 1000, this make sure the jfr evnet always happened. With the original count 100, the jfr event numbers couned to zero intermittely.
> 
> The test jdk/jfr/event/gc/detailed/TestZAllocationStallEvent.java run 10k times all passed after this PR.

SendaoYan has updated the pull request incrementally with one additional commit since the last revision:

  Remove unnecessary explict gc()

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29601/files
  - new: https://git.openjdk.org/jdk/pull/29601/files/5e7f914f..de5fd628

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29601&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29601&range=00-01

  Stats: 10 lines in 1 file changed: 0 ins; 9 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/29601.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29601/head:pull/29601

PR: https://git.openjdk.org/jdk/pull/29601