Fix a test issue

Author: shiltian

clang/test/Misc/warning-flags.c

@@ -18,7 +18,7 @@ This test serves two purposes:
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (58):
+CHECK: Warnings without flags (57):
 
 CHECK-NEXT:   ext_expected_semi_decl_list
 CHECK-NEXT:   ext_missing_whitespace_after_macro_name