erlang: send_after deadline-ordering + cancel-of-fired tests (T3+T4, 769/769)

T3 — concurrent timers fire in deadline order, not schedule order
(scheduler jumps the clock to the earliest pending deadline each
time the runnable queue drains). T4 — cancel_timer on an
already-fired timer returns the atom false.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/erlang/scoreboard.json

@@ -1,7 +1,7 @@
 {
   "language": "erlang",
-  "total_pass": 766,
-  "total": 766,
+  "total_pass": 769,
+  "total": 769,
   "suites": [
     {"name":"tokenize","pass":62,"total":62,"status":"ok"},
     {"name":"parse","pass":52,"total":52,"status":"ok"},
@@ -14,6 +14,6 @@
     {"name":"fib","pass":8,"total":8,"status":"ok"},
     {"name":"ffi","pass":37,"total":37,"status":"ok"},
     {"name":"vm","pass":78,"total":78,"status":"ok"},
-    {"name":"send_after","pass":5,"total":5,"status":"ok"}
+    {"name":"send_after","pass":8,"total":8,"status":"ok"}
   ]
 }