RFR: 8076054 - g1: PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC needs to be removed from source files

[David Lindholm]

Hi,

Please review this fix that removes the macro 
PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC in gc files and fixes the gcc 
warnings for the format strings. Some files had this macro even though 
there were no warnings in them.

This patch deals with all the G1 source files that had this macro. There 
will be separate patches for the other collectors.

Webrev: http://cr.openjdk.java.net/~ehelin/david/8076054/webrev.00/
Bug: https://bugs.openjdk.java.net/browse/JDK-8076054

Testing done: Passed JPRT


Thanks,
David