review request (M) - 4396719 mark sweep stack overflow

[John Coomes]

I'd like reviews of the fix for

4396719 Mark Sweep stack overflow on deeply nested Object arrays

I split the review into two parts in an attempt to make it easier.
The first part fixes the bug by using an explicit stack/queue for
object arrays:

	http://cr.openjdk.java.net/~jcoomes/4396719-objarray/

The second part adds a size parameter to the TaskQueue class; the new
objArray queue used by par compact doesn't need to be as big as the
default queue size, particularly in 64-bit.

	http://cr.openjdk.java.net/~jcoomes/4396719-tqsize/

Performance testing is still in progress.

-John