Instantiate in during as it has no decorators
Make sure object is created before throw matcher

I also start extracting the common behaviour by removing the
current inheritance on other expectations. Next I will create
the abstract common ancestor.
Extract common ancestor for throw expectations
Remove redundancy in matching during call regex

This is to address @ciaranmcnulty notes at
https://github.com/phpspec/phpspec/pull/229#discussion_r8354190
Use $expectation rather than reinstantiating

See https://github.com/phpspec/phpspec/pull/229#discussion_r8354199