Generic `int64` match does not generate correct literal on JS
### Description

Found when trying to remove [these workarounds](https://github.com/nim-lang/Nim/blob/7dfadb8b4e95d09981fbeb01d85b12f23946c3e7/lib/pure/times.nim#L219-L238) from times

```nim
proc foo[T: SomeInteger](a, b: T) =
  let x = a div b

const bar = 123

let x: int64 = 456
foo(x, bar)
```

`bar` is passed as a regular integer `123` to `foo`, when it should be `123n` with `--jsbigint64:on`

### Nim Version

presumably anything after #21613

### Current Output

```text
(node output)

a.js:357
    return a_p0 / b_p1;
                ^

TypeError: Cannot mix BigInt and other types, use explicit conversions
    at divInt64 (a.js:357:17)
    at foo__a_u8 (a.js:662:23)
    at Object.<anonymous> (a.js:673:1)
    at Module._compile (node:internal/modules/cjs/loader:1469:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1548:10)
    at Module.load (node:internal/modules/cjs/loader:1288:32)
    at Module._load (node:internal/modules/cjs/loader:1104:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:174:12)
    at node:internal/main/run_main_module:28:49
```


### Expected Output

```text
no error
```


### Known Workarounds

_No response_

### Additional Information

_No response_