[spec] Switch atan2 to work on Real instead of Numeric.  Add TrigBase argument to it as well.
[spec] Switch atan2 to work on Real instead of Numeric.  Add TrigBase argument to it as well.

git-svn-id: 53605643c415f7495558be95614cf14171f1db78@30622 c213334d-75ef-0310-aa23-eaa082d1ae64

prammer/specs,tokuhirom/specs,tokuhirom/specs,perl6/specs,prammer/specs,prammer/specs,perl6/specs,tokuhirom/specs