[NeonIntrinsicTestEmitter] Add requirement to arm neon intrinsic tests for the feature long_tests.

This will prevent the tests from running on normal make check. You will need to
actually pass in --param run_long_tests=true to LIT in order to run these.
[NeonIntrinsicTestEmitter] Fix incorrect FileCheck pattern where we were expecting a ',' prefix to alignment hints.
[NeonIntrinsicTestEmitter] vld1/vst1 do not require the :64 hint.
Added arm_neon intrinsic tests.

This is a large test and thus it will only run if you pass in --param
run_long_tests=trueto LIT. This is intended so that this test can run on
buildbots and not when one runs make check.