run specific jtreg tests under gdb

[Δημήτρης Μπακαλιος]

Hello all,
I am extending GraalVM to support ShenandoahGC and i am testing it using
jtreg but some tests fail with segmentation fault.So i would like to use
gdb with those specific tests but i can't find a way to do it.The command
that jtreg has on its results forks a new process so that doesnt help.I
run the tests using this command
jtreg -v -jdk:/graal/graal-shenandoah-jdk
 -vmoptions:"-XX:+UnlockDiagnosticVMOptions -XX:+UseShenandoahGC
-XX:-InlineNatives" /jdk/test/hotspot/jtreg/gc/shenandoah
Thanks in advance, i hope i have given enough infos for you to help me