RFR (S): 8181785: Remove the experimental ClearFPUAtPark JVM Flag

[Erik Österlund]

Hi,

There is an experimental JVM flag called ClearFPUAtPark that is used 
only by SPARC. It is turned off by default and is marked as Unsafe and 
Unstable.
The idea is to tell the Solaris kernel not to save floating point 
registers when context switching.
I propose to remove it as it is an unstable option. It relies on an 
implicit unstable OS contract with the kernel that may or may not be 
honored.

Bug: https://bugs.openjdk.java.net/browse/JDK-8181785

Webrev: http://cr.openjdk.java.net/~eosterlund/8181785/webrev.00/

Testing: JPRT

Will need a sponsor.

Thanks,
/Erik