This is not in the spec and does pointless work:
- If either of them is true, we would determine the same result with the
manual code point iteration and comparison
- If neither of them is true, we iterate from the start again and repeat
the work that was just done
Instead, only have the manual loop from the spec and do a length
comparison at the end.
Removing it brings the following microbenchmark from ~5.5s down to ~3.5s
on my machine:
```js
const a = "x".repeat(100_000_000) + "a";
const b = "x".repeat(100_000_000) + "b";
a < b
```
Note that js_rope_string() has been folded into this, the old name was
misleading - it would not always create a rope string, only if both
sides are not empty strings. Use a three-argument create() overload
instead.
Three standalone Cell creation functions remain in the JS namespace:
- js_bigint()
- js_string()
- js_symbol()
All of them are leftovers from early iterations when LibJS still took
inspiration from JSC, which itself has jsString(). Nowadays, we pretty
much exclusively use static create() functions to construct types
allocated on the JS heap, and there's no reason to not do the same for
these.
Also change the return type from BigInt* to NonnullGCPtr<BigInt> while
we're here.
This is patch 1/3, replacement of js_string() and js_symbol() follow.
This will make it easier to support both string types at the same time
while we convert code, and tracking down remaining uses.
One big exception is Value::to_string() in LibJS, where the name is
dictated by the ToString AO.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
Rename it to match the name used by the spec.
Add an override mode to skip formatting numbers with an exponential sign
(e.g. 1e23). This mode is needed by Number and Intl.NumberFormat, who
don't call out a specific number-to-string method to use (they just say
to make "the String consisting of the digits of n").
