Bun integration test is flakey, possibly due to bug in `stream` implementation

[mattt]

The integration test for Bun fails sporadically with a timeout. Re-running usually results in a successful run.

For example, here's a run that failed: https://github.com/replicate/replicate-javascript/actions/runs/8340326500/job/22824063223

And here's the retry, which succeeded: https://github.com/replicate/replicate-javascript/actions/runs/8340326500/job/22824613649

What's concerning is that both predictions succeeded:

• First: https://replicate.com/p/n2h3hilb7s55wccy5f4qif53z4
• Second: https://replicate.com/p/qvsajjdbhkhfr2zlgdxziae4ja

This makes me think that the flakiness is actually a problem in our streaming code. And if we aren't seeing this with the other integration tests, then that suggests a problem in our TextDecoderStream polyfill.