Update nightly to set LC_ALL for comm calls, in addition to sort call.

Back in r22687, I updated nightly to set LC_ALL=C before calling sort. I forgot
to add it to all the comm calls that generate the various sections of the
nightly test report, which is now resolved in this commit.

Discussed with @harshb

git-svn-id: http://svn.code.sf.net/p/chapel/code/trunk@23696 3a8e244f-b0f2-452b-bcba-4c88e055c3ca