JS: fix typos and namings (fixes #24602)

You may noted that I've also changed term of

```
, global "h$vt_double" ||= toJExpr IntV
```

See "IntV"

and

```
  WaitReadOp  -> \[] [fd] -> pure $ PRPrimCall $ returnS (app
"h$waidRead" [fd])
```

See "h$waidRead"