Test Linux with JDK 21

[MarkEWaite]

Exploring the out of memory error report from the Java 21 agents when
packaging the war file.

• Intermittent out of memory for Java 21 builds of Jenkins core on ci.jenkins.io jenkins-infra/helpdesk#3874

[timja]

@MarkEWaite is there a reason you reverted the JVM memory limit? I suspect that will be the fix and I've opened another PR here: #8856

[MarkEWaite]

@MarkEWaite is there a reason you reverted the JVM memory limit? I suspect that will be the fix and I've opened another PR here: #8856

I was trying to check if the problem would happen without the JVM memory limit change. Unfortunately, all 4 draft pull requests passed without the JVM memory limit change.

[timja]

@MarkEWaite is there a reason you reverted the JVM memory limit? I suspect that will be the fix and I've opened another PR here: #8856

I was trying to check if the problem would happen without the JVM memory limit change. Unfortunately, all 4 draft pull requests passed without the JVM memory limit change.

probably needs running in a loop, I had one fail last night for the issue