Fix #1705 where we incorrectly calculate page locations.
Fix #1705 where we incorrectly calculate page locations.

Since we now use an allocation size that isn't a multiple of PAGESIZE, finding
the pages for run_bench wasn't terminating properly.  Now we detect if we've
found enough pages for the allocation and terminate the loop.

xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS