system test: set a maximum html size to process

README.md

@@ -130,6 +130,9 @@ you need to first build and configure nginx.  Set it up something like:
 
         add_header Cache-Control "public, max-age=600";
 
+        # Disable parsing if the size of the HTML exceeds 50kB.
+        pagespeed MaxHtmlParseBytes 50000;
+
         location /mod_pagespeed_test/no_cache/ {
           add_header Cache-Control no-cache;
         }