Handling of OnOutOfMemoryError switches in the SapMachine

Handling of ExitOnOutOfMemoryError, CrashOnOutOfMemoryError, OnOutOfMemoryError and HeapDumpOnOutOfMemoryError in SapMachine differs from upstream OpenJDK.

Behaviorial changes to stock OpenJDK highlighted with italics:

• ExitOnOutOfMemoryError
  • also works for thread exhaustion OOMs
  • also works for direct memory OOMs with system property -Djdk.nio.reportErrorOnDirectMemoryOom=true. Since 17.0.15/21.0.7
  • prints stack to stdout
  • prints "Terminating due to java.lang.OutOfMemoryError" to stdout
  • Exits the VM
• CrashOnOutOfMemoryError
  • also works for thread exhaustion OOMs
  • also works for direct memory OOMs with system property -Djdk.nio.reportErrorOnDirectMemoryOom=true. Since 17.0.15/21.0.7
  • prints stack to stdout
  • Writes an error report (hs_err_pid..)
  • prints "Aborting due to java.lang.OutOfMemoryError" to stdout
  • exits the VM
  • will NOT write a core file unless +CreateCoredumpOnCrash was explicitly specified on the command line
• HeapDumpOnOutOfMemoryError
  • also works for thread exhaustion OOMs
  • also works for direct memory OOMs with system property -Djdk.nio.reportErrorOnDirectMemoryOom=true. Since 17.0.15/21.0.7
  • prints stack to stdout
  • generates heap dump
• OnOutOfMemoryError=command
  • also works for thread exhaustion OOMs (but note that whatever resource exhaustion caused thread creation errors may cause the subsequent fork for command to fail as well)
  • prints stack to stdout
  • invokes the given command

Notes:

• Avoiding core file creation with CrashOnOutOfMemoryError is intentional. CrashOnOutOfMemoryError is by default tuned to shut the VM down with a minimum of fuzz while still giving us a useful error report. If a core file is wanted for post analysis, specify -XX:+CreateCoreDumpOnCrash.
• For thread creation errors, xxxOnOutOfMemoryError switches are handled before the JVMTI ResourceExhausted event is posted. This means that JVMTI agents monitoring this event (e.g. CloundFoundry's jvmkill) may not get invoked. This is intentional.
• The SapMachine-specific flag ExitVMOnOutOfMemoryError (note the "VM" in the name, not to be confused with ExitOnOutOfMemoryError) is an alias to CrashOnOutOfMemoryError and provided for backward compatibility reasons.