Web Inspector: REGRESSION(r242018): using `RegExp.prototype.test` with a global `RegExp` will ignore one potential match after each successful match

[Devin Rousso]

```
    let x = /script/gi;
    console.log(x.test("script")); // true
    console.log(x.test("script")); // false
    console.log(x.test("script")); // true
    console.log(x.test("script")); // false
```

this is due to the nature of `lastIndex`, which is set when using a global `RegExp` (see 12.a in <https://tc39.es/ecma262/#sec-regexpbuiltinexec>)

[Devin Rousso]

Created attachment 396795 [details]
Patch

[Devin Rousso]

Created attachment 396797 [details]
Patch

use better names :P

[Radar WebKit Bug Importer]

<rdar://problem/61950043>

[EWS]

Committed r260291: <https://trac.webkit.org/changeset/260291>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 396797 [details].

[BJ Burg]

(In reply to Devin Rousso from comment #0)
> ```
>     let x = /script/gi;
>     console.log(x.test("script")); // true
>     console.log(x.test("script")); // false
>     console.log(x.test("script")); // true
>     console.log(x.test("script")); // false
> ```
> 
> this is due to the nature of `lastIndex`, which is set when using a global
> `RegExp` (see 12.a in <https://tc39.es/ecma262/#sec-regexpbuiltinexec>)


Wut.