Change JVM options with small ranges from 64 to 32 bits, for gc_globals.hpp

The declarations of JVM options, whose ranges are small values, should be changes from 64 bits to 32 bits. For example, AdaptiveTimeWeight is declared as a uintx but need only be a uint.

   product(uintx, AdaptiveTimeWeight, 25, \
           "Weight given to time in adaptive policy, between 0 and 100") \
           range(0, 100) \

Changing AdaptiveTimeWeight to a uint prevents -Wconversion compiler warnings when it is assigned to variables declared as uint's.