Remove the incorrect tests that use a negative offset for mmap without
a fd.
Add a small set of tests for mmap.
Bug: 15436969
Change-Id: Id537d33cd4cdc26dee6cdfa9bf9cf35754bce335
We don't actually need to worry about sign extension if we reject
negative values ourselves. Previously it was possible to come up
with negative but aligned values that we would pass to the kernel;
in the case of mmap (as opposed to mmap64) we'd incorrectly turn
those into large positive offsets.
Change-Id: I2aa583e0f892d59bb77429aea8730b72db32dcb0
