Components that throw during mount doesn't remount after HMR

[samfundev]

Describe the bug

If a component throws while being mounted, that would normally be fine because the developer could fix the code and Svelte would remount the component using HMR. But now, even without having async enabled, HMR fails to remount the component. I've bisected this down to #15844. And found a potential fix which I've made a PR for.

Reproduction

The following reproductions are the same except for the version of Svelte and have a line of code that can be toggled on or off to have the component throw when it mounts.

latest (5.50.1): https://www.sveltelab.dev/32149g118o5egv7
pre-async (5.35.7): https://www.sveltelab.dev/3032460y2gelaoq

Reproduction steps:

1. Mount a component that has been compiled using the hmr compiler option.
2. Hot reload the component but have the component throw an exception on mount.
3. Hot reload the component but without an exception during mount.

(this excludes the playground since it doesn't use hmr: true)

Logs

System Info

n/a

Severity

annoyance