Merge "Allocate a contiguous region of virtual memory to be subdivided among the...

Merge "Allocate a contiguous region of virtual memory to be subdivided among the various heaps managed by the garbage collector.  Because we cannot tell how far the break has been advanced by morecore, we over allocate virtual memory and grain each heap on a multiple of the maximum heap size.  If we could reckon the position of the break, we could allocate just as many pages as required.  This requires exporting more state from mspace.c, a refinement I will reserve for a future change list." into dalvik-dev