[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.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184784 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed