Remove use of builtin comma operator.

Cleanup for upcoming Clang warning -Wcomma.  No functionality change intended.

llvm-svn: 261271
diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index 407ccea..060055f 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -707,7 +707,8 @@
       } else if (*cur == 0x0A)  // LF
         break;
 
-      ++cur, ++next;
+      ++cur;
+      ++next;
     }
   }