324181 was previously closed with a solution to always make
MAP_32BIT fail. This is technically correct/according to the doc,
but is not very usable.
This patch ensures that MAP_32BIT mmap is succesful, as long as
aspacemgr gives a range in the first 2GB
(so, compared to a native run, MAP_32BIT will fail much more quickly
as aspacemgr does not reserve the address space below 2GB on a 64 bits).
Far to be perfect, but this is better than nothing.
Added a regression test that test succesful mmap 32 bits till
the 2GB limit is reached.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15341
