test: make ratelimit.test tap-compatible

Part of #7618

NO_DOC=internal
NO_CHANGELOG=internal

test/unit/ratelimit.c

 #include <time.h>
 
+#define UNIT_TAP_COMPATIBLE 1
 #include "unit.h"
 #include "ratelimit.h"
 

test/unit/ratelimit.result

-	*** main ***
-1..10
-ok 1 - emitted 10 expected 10
-ok 2 - suppressed 0 expected 0
-ok 3 - emitted 0 expected 0
-ok 4 - suppressed 0 expected 0
-ok 5 - emitted 1 expected 1
-ok 6 - suppressed 10 expected 10
-ok 7 - emitted 1 expected 1
-ok 8 - suppressed 0 expected 0
-ok 9 - emitted 1000 expected 1000
-ok 10 - suppressed 3000 expected 3000
-	*** main: done ***