Results clipped after first error with `.WithErrors()`

[zoido]

When the Result Pool is configured WithErrors results after fir error are clipped.

• Affected version: trunk.
• 0.3.0 does not have this problem.
• Introduced in Make result order deterministic #126

Minimal Example

package main

import (
	"errors"
	"fmt"

	"github.com/sourcegraph/conc/pool"
)

func main() {
	p := pool.NewWithResults[int]().WithErrors()
	p.Go(func() (int, error) { return 1, nil })
	p.Go(func() (int, error) { return 2, errors.New("an error") })
	p.Go(func() (int, error) { return 3, nil })

	got, _ := p.Wait()
	fmt.Println(got) // Outputs [1]
}

Expected output: [1 3]