feat(test): improved op sanitizer errors + traces (#13676)

This commit improves the error messages for the `deno test` async op
sanitizer. It does this in two ways:
- it uses handwritten error messages for each op that could be leaking
- it includes traces showing where each op was started

This "async op tracing" functionality is a new feature in deno_core.
It likely has a significant performance impact, which is why it is only
enabled in tests.

1 files changed, 5 insertions, 3 deletions

diff --git a/cli/tests/unit/timers_test.ts b/cli/tests/unit/timers_test.ts
index 7312a6440..e85a2effc 100644
--- a/cli/tests/unit/timers_test.ts
+++ b/cli/tests/unit/timers_test.ts
@@ -397,10 +397,12 @@ Deno.test(async function timerMaxCpuBug() {
   clearTimeout(setTimeout(() => {}, 1000));
   // We can check this by counting how many ops have triggered in the interim.
   // Certainly less than 10 ops should have been dispatched in next 100 ms.
-  const { opsDispatched } = Deno.metrics();
+  const { ops: pre } = Deno.metrics();
   await delay(100);
-  const opsDispatched_ = Deno.metrics().opsDispatched;
-  assert(opsDispatched_ - opsDispatched < 10);
+  const { ops: post } = Deno.metrics();
+  const before = pre.op_sleep.opsDispatched;
+  const after = post.op_sleep.opsDispatched;
+  assert(after - before < 10);
 });
 
 Deno.test(async function timerOrdering() {