fix(ngRoute): pipe preceding route param no longer masks ? or * operator

Before this change,

```js
$routeProvider.when('/foo/:bar|?', { ... });
```

would not have the expected effect --- the parameter would not be optional, and
the pipe would not be included in the parameter name.

Following this change, the presence of the pipe operator will typically cause an
exception to be thrown due to the fact that the generated regexp is invalid.

The net result of this change is that ? and * operators will not be masked, and
pipe operators will need to be removed, although it's unexpected that these are
being used anywhere.

Closes #5920