LibWeb/Layout: Vector lookup overflow on responsive resize

[manuel-za]

Fixes #3976:

• Triggered on relayout when changing the size or zoom level for a responsive document.
• An image node's containing block switches between alignments on a new size.
• The image node is not included in the containing block's line boxes.

There is another unprotected vector lookup below. Seems like that one is logically sound (fragment_index from linebox_index) so I didn't protect or assert that, but added a FIXME.

Added a test (crash before; success now).

[manuel-za]

@kalenikaliaksandr this touched your code, so maybe you can take a look? Thanks!

[SINF-KEN]

up

[manuel-za]

up

?

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

[github-actions[bot]]

This pull request has been closed because it has not had recent activity. Feel free to open a new pull request if you wish to still contribute these changes. Thank you for your contributions!