Fixes #2242 : Make exceptions for Inorder.verify more standard / spec…

[devintark]

…ific

*Adds NullInsteadOfMockException and NotAMockException checks to Inorder.verify() before checking if mocks were passed in during creation of Inorder

See #2242 for a description of the issue.

Inorder.verify(mock) now first checks if the passed argument is null, and if the mock is in fact a mock, and gives appropriate Exception messages, before checking if the passed in argument was passed during creation of Inorder object, and therefore giving a less specific error message.

Checklist

• [x ] Read the contributing guide
• [ x] PR should be motivated, i.e. what does it fix, why, and if relevant how
• [ x] If possible / relevant include an example in the description, that could help all readers
  including project members to get a better picture of the change
• [x ] Avoid other runtime dependencies
• [x ] Meaningful commit history ; intention is important please rebase your commit history so that each
  commit is meaningful and help the people that will explore a change in 2 years
• [x ] The pull request follows coding style
• [ x] Mention Fixes #<issue number> in the description if relevant
• [ x] At least one commit should mention Fixes #<issue number> if relevant

[TimvdLippe]

Thanks!

[mjustin]

Indeed, thanks!