F.open() doesn't throw when violating same-origin

You can't, for example, load google.com from localhost. This fails, but does so silently.

We do catch the error in a try/catch [here](https://github.com/bitovi/funcunit/blob/874b4f9fe8870080b5070139e67d72a8fd3e52d7/browser/open.js#L274). We could improve this by checking the error in the catch and if it is a SecurityError, rethrow so the user can see the error.

Chrome and Firefox give a different error message, so detecting this might be tricky.

Start at browser/open.js around line 274, where the error is caught after F.open() attempts a cross-origin load. Compare the SecurityError behavior in Chrome and Firefox, then make the violation visible instead of silently catching it. Done means the same-origin failure is rethrown and covered for the reported behavior.

Written by the indexing model from the issue text.