[11u] RFR: 8231949: [PPC64, s390]: Make async profiling more reliable

[Doerr, Martin]

Hi,

I'd like to backport "8231949: [PPC64, s390]: Make async profiling more reliable" to 11u-dev.
It applies almost cleanly. I only need to adapt to older signature of is_valid_method and Metaspace::contains in thread_linux_ppc.cpp and thread_linux_s390.cpp:
-      if (!Method::is_valid_method(m)) return false;
-      if (!Metaspace::contains(m->constMethod())) return false;
+      if (m == NULL || !m->is_valid_method()) return false;
+      if (!Metaspace::contains((const void*)m->constMethod())) return false;

While discussing backport of "8221539: [metaspace] Improve MetaspaceObj::is_metaspace_obj() and friends" we had decided not to backport dependent changes, so I think such signature adaptations are needed for jdk11u backports, now.

Orignial bug:
https://bugs.openjdk.java.net/browse/JDK-8231949

Original change:
https://hg.openjdk.java.net/jdk/jdk/rev/c6cbcc673cd3

Backport webrev:
http://cr.openjdk.java.net/~mdoerr/8231949_get_top_frame_for_profiling/11u-webrev.00/

Best regards,
Martin