review request (M) - 6725714 add a table to speed up bitmap searches

[John Coomes]

Please review the following change which adds a new table (the
'BlockTable') to the parallel compacting collector:

	http://cr.openjdk.java.net/~jcoomes/6725714-blocktable/

I've run a number of test suites (vm.regression, vm.gc, vm.runtime,
nsk.stress, nsk.monitoring, vm.compiler) in 32- and 64-bit on solaris
and/or linux.

-John