Check the libuv, OpenSSL and libxml2 memory context on exit

As we can't check the deallocations done in the library memory contexts
by default because it would always fail on non-clean exit (that happens
on error or by calling exit() early), we just want to enable the checks
to be done on normal exit.

bin/named/main.c

@@ -1584,6 +1584,10 @@ main(int argc, char *argv[]) {
 			     &named_g_taskmgr);
 	isc_mem_checkdestroyed(stderr);
 
+	isc__tls_setdestroycheck(true);
+	isc__uv_setdestroycheck(true);
+	isc__xml_setdestroycheck(true);
+
 	named_main_setmemstats(NULL);
 
 	named_os_closedevnull();