Disable large heap sysmon messages

I like large heaps and I can not lie.

(cherry picked from commit 41fcb58)

Author: lukebakken

src/rabbit.erl

@@ -582,7 +582,7 @@ ensure_sysmon_handler_app_config() ->
                 {port_limit, 100},
                 {gc_ms_limit, 0},
                 {schedule_ms_limit, 0},
-                {heap_word_limit, 10485760},
+                {heap_word_limit, 0},
                 {busy_port, false},
                 {busy_dist_port, true}
                ],