Fix exception class in InvocationMocker und MockBuilder strub

[weph]

After enabling checkForThrowsDocblock psalm crashed with

Uncaught Exception: Could not get class storage for phpunit\framework\mockobject\builder\runtimeexception

I had a look at PHPUnit and there really isn't a RuntimeException in that namespaces and after browsing through some versions I think there never has been. So I guess what's really meant is the global one.

[weirdan]

I fixed test failures on master, mind rebasing this? I can't push to your repo, either because you did not enable 'Updates from maintainers' checkbox or because the PR was created from weph:master and not from a dedicated branch.

[weph]

I checked "Allow edits by maintainers" and according to the help text you should be allowed to push to my master 🤷🏻‍♂️
But anyway... I just rebased it

[weirdan]

Thanks!

[weirdan]

Released in 0.15.2.