[11u] RFR 8202884: SA: Attach/detach might fail on Linux if debugee application create/destroy threads during attaching

[Langer, Christoph]

Hi,

please review the backport of 8202884 to jdk11u-dev:

Bug: https://bugs.openjdk.java.net/browse/JDK-8202884
Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8202884.jdk11u-dev/

It applied cleanly, except from some header mismatch in src/jdk.hotspot.agent/linux/native/libsaproc/ps_proc.c.

Thanks
Christoph