[OPENMP] Allow skip expression after comma in clauses with lists.

Compatibility fix for better compatibility with the existing software.

llvm-svn: 265003
diff --git a/clang/test/OpenMP/parallel_sections_reduction_messages.cpp b/clang/test/OpenMP/parallel_sections_reduction_messages.cpp
index 52d4cb9..8b72f99 100644
--- a/clang/test/OpenMP/parallel_sections_reduction_messages.cpp
+++ b/clang/test/OpenMP/parallel_sections_reduction_messages.cpp
@@ -113,7 +113,7 @@
   {
     foo();
   }
-#pragma omp parallel sections reduction(| : argc, // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}} expected-error {{invalid operands to binary expression ('float' and 'float')}}
+#pragma omp parallel sections reduction(| : argc, // expected-error {{expected ')'}} expected-note {{to match this '('}} expected-error {{invalid operands to binary expression ('float' and 'float')}}
   {
     foo();
   }
@@ -266,7 +266,7 @@
   {
     foo();
   }
-#pragma omp parallel sections reduction(| : argc, // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+#pragma omp parallel sections reduction(| : argc, // expected-error {{expected ')'}} expected-note {{to match this '('}}
   {
     foo();
   }