Set the FPCR.FZ bit before running tests using ARM NEON,
in order to make tests pass for most opcodes.

Add a way to check for expected failures in the test suite,
since ARM NEON does not comply to IEEE754.

Errors are expected when using divf (resp. sqrtf) on large
(resp. small) numbers.

Fixes #33, #20

Signed-off-by: Gaetan Bahl <gaetan.bahl@nxp.com>