XS truncates non-decimal bigint toString output

[gibson042]

Environment: XS 17.9.1, slot 32 bytes, ID 4 bytes

Description
BigInt.prototype.toString with a radix of 2, 8, or 16 is incorrectly truncated (and in the case of base 8, apparently truncated at an internal boundary that changes an output character).

Steps to Reproduce

const numberMax = BigInt(Number.MAX_VALUE);
print(numberMax.toString(16));
print(numberMax.toString(8));
print(numberMax.toString(2));

Actual behavior

fffffffffffff80000000000
77777777777777777600000000000000
111111111111111111111111111111111111111111111111111110000000000000000000000000000000000000000000

Expected behavior

fffffffffffff800000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
177777777777777777400000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
1111111111111111111111111111111111111111111111111111100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-bigint.prototype.tostring

[phoddie]

Thanks for the report. This is almost certainly the result of relatively recent optimizations to the BigInt to string conversion. We'll take a look.