[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/sections_private_messages.cpp b/clang/test/OpenMP/sections_private_messages.cpp
index 27bb313..2855a7d 100644
--- a/clang/test/OpenMP/sections_private_messages.cpp
+++ b/clang/test/OpenMP/sections_private_messages.cpp
@@ -124,7 +124,7 @@
   {
     foo();
   }
-#pragma omp sections private(argc, // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+#pragma omp sections private(argc, // expected-error {{expected ')'}} expected-note {{to match this '('}}
   {
     foo();
   }
@@ -214,7 +214,7 @@
   {
     foo();
   }
-#pragma omp sections private(argc, // expected-error {{expected expression}} expected-error {{expected ')'}} expected-note {{to match this '('}}
+#pragma omp sections private(argc, // expected-error {{expected ')'}} expected-note {{to match this '('}}
   {
     foo();
   }