Fix confusing error message from create1 test

Used to accidentally hex encode output of OpenFlags stringifier.
Test create1 does not insist on seeing O_TRUNC

After all, it is a Create, so O_TRUNC does not matter. Apparently OS X
does not pass that through in this case.
Fix confusing error message from open test

Used to accidentally hex encode output of OpenFlags stringifier.
Test open disables OpenDirectIO to avoid triggering OSXFUSE limitation