Rollup merge of rust-lang#104201 - GuillaumeGomez:gui-test-check-file…

…-errors, r=notriddle

Add check in GUI test for file loading failure

Since rust-lang#101702, some resources location need to be updated in case their content changed because then their hash will change too. This will prevent errors like rust-lang#104114 to happen again.

The second commit is to prevent CORS errors: when a file is linked from a file itself imported, the web browser considers they come from a different domain and therefore triggers the error. The option tells the web browser to ignore this case.

cc ```@jsha```
r? ```@notriddle```