patch 8.0.0198: some syntax arguments take effect even after "if 0"

Problem:    Some syntax arguments take effect even after "if 0". (Taylor
            Venable)
Solution:   Properly skip the syntax statements.  Make "syn case" and "syn
            conceal" report the current state.  Fix that "syn clear" didn't
            reset the conceal flag.  Add tests for :syntax skipping properly.

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    198,
 /**/
     197,
 /**/