RFR: 8201213: Remove INCLUDE_ALL_GCS from memset_with_concurrent_readers

[Stefan Karlsson]

Hi all,

Please review this patch to remove the INCLUDE_ALL_GCS checks from 
memset_with_concurrent_readers.

http://cr.openjdk.java.net/~stefank/8201213/webrev.01/
https://bugs.openjdk.java.net/browse/JDK-8201213

This only marginally reduces the libjvm.so size, and it would be easier 
to implement JDK-820729 without it, so I propose that we remove these 
checks.

Thanks,
StefanK