Same hygiene sweep as the previous commits, applied to the three tests
whose own subject is a fault or cleanup path that, if it regressed, would
leave a receiveFrame() call with nothing to ever resolve or reject it:
the two "fix 1" throwing-handler tests (a malformed frame that should
fault the connection, and a peer shutdown that should run cleanup()) and
the "fix 3" peer-shutdown test. Each now wraps its transport in
try/finally and uses receiveFrameOrTimeout() instead of a bare
receiveFrame() behind assert.rejects.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2cd63f3ee9