RFC: JEP: Deprecate the Parallel Scavenge / Serial Old collector combination

[Thomas Schatzl]

Hi all,

   the Oracle gc team would like to deprecate the parallel scavenge / 
serial old collector combination enabled by using -XX:+UseParallelGC 
-XX:-UseParallelOldGC.

This seems to be an extremely rarely used collector combination, as at 
last OCW in August with ~100? Java users/devs nobody seemed to know it, 
but it still takes some resources away that may be used for other issues.

This is only the *deprecation* effort - there is no change in 
functionality except for a "this collector combination is deprecated"2 
at this time.

I wrote up a JEP draft at https://bugs.openjdk.java.net/browse/JDK-8229492 .

Comments and reviewers to move it along appreciated.

Thanks,
   Thomas