Moved SET_LINENO up a couple of lines in one compiler function.

[trivial; pre-reviewed by Tom]

This is a minor follow-up to r21773. If we are doing SET_LINENO,
may as well have it cover a couple more nodes being created.


git-svn-id: http://svn.code.sf.net/p/chapel/code/trunk@21848 3a8e244f-b0f2-452b-bcba-4c88e055c3ca