bug: can't return a tuple created on the fly from a var function

git-svn-id: http://svn.code.sf.net/p/chapel/code/trunk@23599 3a8e244f-b0f2-452b-bcba-4c88e055c3ca
Regression due to r23459 was fixed by tvandoren.

git-svn-id: http://svn.code.sf.net/p/chapel/code/trunk@23600 3a8e244f-b0f2-452b-bcba-4c88e055c3ca