"\u{FFFFFFF}" is marked as early instead of fail

[bakkot]

This just doesn't match the grammar at all: see
https://tc39.github.io/ecma262/#prod-CodePoint

Incorrect tests:

• early/14eaa7e71c682461.js
• early/aca911e336954a5b.js

[michaelficarra]

That's because this has changed since the tests were added. It was me actually: https://github.com/tc39/ecma262/pull/773/files#diff-3540caefa502006d8a33cb1385720803L10016