test: add test-worker-prof to the SLOW list for debug

Consistently failing on ubuntu1804_sharedlibs_debug_x64

Refs: #26401

PR-URL: #32589
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

test/root.status

@@ -153,6 +153,7 @@ sequential/test-inspector-port-cluster: SLOW
 sequential/test-net-bytes-per-incoming-chunk-overhead: SLOW
 sequential/test-pipe: SLOW
 sequential/test-util-debug: SLOW
+sequential/test-worker-prof: SLOW
 
 [$type==coverage]
 async-hooks/test-callback-error: PASS,FAIL,CRASH