When re-symbolication splits funcs, discard any call tree transforms that refer to these funcs (avoid non-sensical state)

Reported in https://github.com/firefox-devtools/profiler/pull/2515#discussion_r423111362 :

> Ah, this isn't handled.
>
> STR:
>
> * Go to: https://deploy-preview-2515--perf-html.netlify.app/public/b9ef18c1453fc60ae8dd3281896a1eadd9ce1b10/
> * Focus on subtree for "g_main_context_iterate"
> * Re-symbolicate
>
>
> Expected result:
>
> * The invalidated transforms should either be updated or removed.
>
>
> Actual result:
>
> * The invalidated call node path is still being applied, creating an empty call tree.
>
>
> Here is a screenshot with more transforms applied.
> 
>
> I think ideally we should explicitly invalidate call node paths in our state anytime we split functions, otherwise our UI can be in a non-sensical state.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-264)