Add option to remove pattern match failure assertions

[natefaubion]

In line with the main compiler, we insert pattern match failure assertions ($runtime.fail()) when there is no wildcard pattern. Since the pattern matching tree optimizer emits complete if/else trees, we should be able to omit the assertion when a branch covers all tags for a given ProperName.

This failure assertion is potentially useful for catching foreign errors sneaking through, so I think this could be an option like --int-tags.