RFR (XXS): 8231553: Deprecate unused G1RSetScanBlockSize command line option

[Thomas Schatzl]

Hi all,

   can I have reviews for the changeset to start the removal process for 
the G1RSetScanBlockSize option? In JDK-8213108 we removed its (only) 
use, so we should get rid of the option.

There is also a CSR for that (JDK-8231568) for which I need reviewers.

CR:
https://bugs.openjdk.java.net/browse/JDK-8231553
Webrev:
http://cr.openjdk.java.net/~tschatzl/8231553/webrev
Testing:
local compilation, make sure that the deprecation message shows up

Thanks,
   Thomaas