Allow non word aligned heap limit for space bitmap

For the mem map large object space, the bitmap covers the entire
range of memory. This is done by passing in max int as the space
capacity. Previously, the space bitmap heap limit was computed by
multiplying the number of words by the word stride. In 32 bit systems
this caused heap limit to be (1 << 32) == 0 for the mem map large
object space.

This CL allows storing max int as the heap limit and returning that
from the function.

Added regression test to large object test.

Test: verify lyft installs and launches with the profile that was causing problems
Test: test-art-host

Bug: 64413646

Change-Id: Ic51aec047d37d905846717dfb4aa1c8198908df9