RFR: 8223147: JFR Backport (to jdk8u)

[DDH]

Hi Mario:

All patch sets we provided are incremental changes based on Azul' patch set,
are only for 8, and the features in these patches are available in 11.

For example:
Thread Sampling Support can be found in
http://hg.openjdk.java.net/jdk/jdk11/file/1ddf9a99e4ad/src/hotspot/share/jfr/periodic/sampling

The description of our issues may be not clear, we will update the description later.
Sorry for the misunderstanding.

Thanks,
Denghui