test($compile): add test for optional `require` in directives with `^` operator
test($compile): add test for optional `require` in directives with `^` operator

The directive property `require` allows optional requirement via
the `?` before or after the `^` operator. Add tests to ensure this
functionality is not lost inadvertently.

Closes #9391
Closes #9392

ggershoni/angular.js,ggershoni/angular.js,ggershoni/angular.js,ggershoni/angular.js