quarantine 'em

Additionally, there's an incredibly small number of cases where `0xfff...f` represents the same float as `0x1000...0` but saves a character

The same is true in base 10 (i.e. `999...9` represents the same float as `1000...0` but saves a character) but by then you're using `1e21`

Handling numbers in general, not just numeric literals, has far more pitfalls and potential for optimisation

An earlier version of UglifyJS naively replaced `Infinity` with `1/0`, but that turned e.g. `x/Infinity` into `x/1/0`

It also replaced `NaN` with `0/0`, turning `x/NaN` (always `NaN`) into `x/0/0` (`Infinity`, `-Infinity`, `NaN`) and SAVING NO CHARACTERS

`1<<17` is shorter than `131072`. `~99` is shorter than `-100`. `1e9-7` is shorter than `999999993`. But when is such a substitution safe?

And it turns out the number crunching to determine the shortest possible expression of an arbitrary float is deep and complicated

`.1+.2` is shorter than `0.30000000000000004` but, starting from the latter, how in the WORLD would you get the former?