libvulkan: Enable integer sanitization

libvulkan: Enable integer sanitization

This causes the compiler to add runtime checks for undefined (e.g.
shift by larger than bitwidth) or suspicious (e.g. unsigned integer
overflow) operations. The process will abort if they occur.

In particular, we do many allocations of the form pfnAllocation(n *
sizeof(T)); if 'n' is large these will overflow and we'll allocate
less memory than expected, possibly leading to exploitable buffer
overruns.

Requested during security audit in bug 27118888.

Change-Id: Id81c94595579df034b948a40270f164e38635070