This overrides, on each Uint8Array returned from an introspected function
or from ByteArray.fromString() or ByteArray.fromGBytes(), the toString()
property with a compatibility shim that preserves the old behaviour of
ByteArray.prototype.toString() while logging a compatibility warning
asking people to fix their code.

This ByteArray.toString() -> Uint8Array.toString() change has had more
fallout in application code than I expected, so it seems better to
preserve backwards compatibility. (The old behaviour was to decode the
byte array into a string with default encoding UTF-8, and the default
behaviour of Uint8Array is to return a string with the decimal digits of
each byte joined with commas. So the effect was that strings like
"97,98,99,100" would show up in UIs where previously "abcd" would have
been printed.

This is only on specific instances, so Uint8Array.prototype.toString()
remains untouched.