[11u] Intended JFR related backports

[Jaroslav Bachorík]

Hi all,

this is a heads-up for the intended JFR related backports.
The main issue is JDK-8225797: OldObjectSample event creates unexpected
amount of checkpoint data

However, due to major differences between the dev and 11u also the
following ports are required (in the order they are to be applied):
- JDK-8209850: Allow NamedThreads to use GlobalCounter critical sections
(clean apply)
- JDK-8209976: Improve iteration over non-JavaThreads (1-line change to
resolve conflicts)
- JDK-8210024: JFR calls virtual is_Java_thread from ~Thread() (1-line
change to resolve conflicts)
- JDK-8214850: Rename vm_operations.?pp files to vmOperations.?pp files
(simple change to resolve conflicts)
- JDK-8209802: Garbage collectors should register JFR types themselves to
avoid build errors (slightly more involved changes to resolve conflicts)

At the moment I am waiting for the resolution of JDK-8231081 and will post
RFRs only once that issue is resolved and I can include it in the backport
set.

Cheers,

-JB-