6677708: G1: re-enable parallel RSet updating and scanning

Summary: Enable parallel RSet updating and scanning.
Reviewed-by: iveresov, jmasa

src/share/vm/gc_implementation/g1/g1_globals.hpp

@@ -267,11 +267,11 @@
   product(uintx, G1HeapRegionSize, 0,                                       \
           "Size of the G1 regions.")                                        \
                                                                             \
-  experimental(bool, G1UseParallelRSetUpdating, false,                      \
+  experimental(bool, G1UseParallelRSetUpdating, true,                       \
           "Enables the parallelization of remembered set updating "         \
           "during evacuation pauses")                                       \
                                                                             \
-  experimental(bool, G1UseParallelRSetScanning, false,                      \
+  experimental(bool, G1UseParallelRSetScanning, true,                       \
           "Enables the parallelization of remembered set scanning "         \
           "during evacuation pauses")                                       \
                                                                             \