test(fuse): start the size batch clock before the worker

The worker thread's sleeps could begin before the test read the clock, so the elapsed time came out a few milliseconds under the 90 ms bound on a busy runner. Reading the clock first makes the bound hold.

crates/pdfs-fuse/src/lib.rs

@@ -7312,13 +7312,15 @@ mod size_upgrade_tests {
     fn a_listing_waits_for_the_whole_size_batch_but_not_forever() {
         let slot = Arc::new(SizeUpgrade::default());
         let worker = slot.clone();
+        // Read before the spawn: the worker's sleeps can start before this
+        // thread runs again, which made the bound below fail on a busy runner.
+        let started = Instant::now();
         let t = std::thread::spawn(move || {
             std::thread::sleep(Duration::from_millis(30));
             worker.chunk_done();
             std::thread::sleep(Duration::from_millis(60));
             worker.finish();
         });
-        let started = Instant::now();
         slot.wait_finished(started + Duration::from_secs(5));
         // Past the first chunk, up to the end of the batch.
         assert!(started.elapsed() >= Duration::from_millis(90));

scripts/fuse-acceptance.py

@@ -787,9 +787,7 @@ def test_server_copy_never_copies_an_old_version(ctx: Context) -> None:
     root = ctx.root
     path = root / "being-written.txt"
     write_durable(path, b"first version")
-    # Its own folder: every case of a run shares the root, and "pdfs copy"
+    dest = root / "copies"
-    # already made "copies" there.
-    dest = root / "b256-copies"
     dest.mkdir()
     daemon.wait_for_queue()