fix(fuse): keep a move that lands while its create is read back (B161)

adopt_real_uid asked whether a move was queued only after reading the
node back. A move that landed in between left no op, and the answer still
had the old name, so the mount showed the file under it. Ask first.

The fake Drive can hold a read's answer (hold_answer_to_next_read) so the
test can land the move while the answer is on its way.

docs/CHANGELOG.md

@@ -49,6 +49,8 @@ by its local id, in the queue, the stored tree and pins alike.
 - **Opening a file right after the daemon restarts no longer fails with "Resource temporarily
   unavailable"** (B159).
 - **A new folder reaches Drive at once**, not up to half a minute later (B160).
+- **A file moved while it was still being uploaded keeps its new name in the mount** on a slow
+  link (B161).
 - **A file renamed just as its upload finished keeps its new name.** The mount no longer showed
   the old name, and a second rename no longer failed with "No such file or directory" (B152).
 - **A change that waits for a name to be freed no longer waits seconds after it is.** A rename or