Caused by incorrectly using mutable `ListBase` iterator, which caused
adding same strip to meta twice. This caused `next` and `prev` fields
to be set to same value resulting in infinite loop in next iterator.
Since multiple strips can be removed from list in one iteration, collect
these into `VectorSet` and move them in separate for loop.
Also do cache invalidation while strips are in original `seqbase`,
otherwise it can skip invalidation of strips downstream.
Pull Request: https://projects.blender.org/blender/blender/pulls/127951
8da413877b