[flang] Fix test after 4078afc

This tests requires the OpenMP runtime to be present, but the way that
the lit config detects it fails when "openmp" is added to RUNTIMES
instead of PROJECTS. This caused the tests to be skipped as unsupported
in local and upstream tests.

The actual bug was a missing word in the message, and putting the check
at the wrong line.

flang/test/Semantics/OpenMP/clause-validity01.f90

@@ -342,8 +342,8 @@
   a = 1.0
   !ERROR: COPYPRIVATE clause is not allowed on the END WORKSHARE directive
   !$omp end workshare nowait copyprivate(a)
+  !ERROR: NOWAIT clause is not allowed on the OMP WORKSHARE directive, use it on OMP END WORKSHARE directive 
   !$omp workshare nowait
-  !ERROR: NOWAIT clause is not allowed on the WORKSHARE directive, use it on OMP END WORKSHARE directive
   !$omp end workshare
   !$omp end parallel