8039743: Use correct format specifier to print size_t values and pointers in the GC code

[Stefan Karlsson]

Hi all,

There are a number of occurrence in HotSpot that use %d and 0x%x to 
print size_t values and pointers. This is incorrect on platforms that 
have different type sizes for size_t and pointers compared to ints.

This patch only touches the GC code, but is based on an larger patch 
from Mikael Vidstedt.

http://cr.openjdk.java.net/~stefank/8039743/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8039743

thanks,
StefanK