RFR(9): 8176098: Deprecate FlatProfiler

[Robbin Ehn]

Hi all, please review:

The VM Option "-Xprof" no longer relevant and is a source of root scanning and contains bugs.

The FC Extension Request have been approved and CCC is pending approval.

Webrev:
http://cr.openjdk.java.net/~rehn/8176098/jdk/webrev/
http://cr.openjdk.java.net/~rehn/8176098/hotspot/webrev/

Bug:
https://bugs.openjdk.java.net/browse/JDK-8176098

No test is affected by this new warning. (there is an internal test but it's no in use)

Thanks!

/Robbin