Modified modules must be reloaded before running the "after patches" step

If a module is modified by the patchset we are going to test, its unmodified version is used to run the tests. Actually this problem only appears for the TT tests.

For instance, in the same patchset:

• A module is adding Koha::Patron->test
• The template is calling [% patron.test %]

valid_template check will fail with The method Koha::Patron->test is not covered by tests!, which actually means the module does not have a test method.