Evaluate some BigInt operations

[fabiosantoscode]

Not confident enough to release this right now because handling BigInt can cause a bunch of TypeErrors, both in Terser and output code.

[fabiosantoscode]

To do: avoid dividing by zero!

[dead-claudia]

To do: avoid dividing by zero!

@fabiosantoscode You might be able to get away with a sentinel value (say, a special object or symbol) and using that for a synthetic "not-a-number" value for bigints. That may be easier to fuse in since it'll require less code motion. Then, in the end, you can render that synthetic value to a single representation like 0n/0n (along with maybe a compiler warning) to ensure the TypeError ultimately gets thrown in the end.

[fabiosantoscode]

I think I'll just make 1234n / 0n transform into itself (simply return this). This is way too much of a corner case in my opinion, if someone wrote code that will 100% crash they can afford a couple extra bytes, nobody does this normally

[fabiosantoscode]

The TODO was just to avoid Terser itself crashing

[dead-claudia]

@fabiosantoscode Fair enough. I was just giving a stray suggestion.