Added event for clearing PageFactory loop detection buffer after method end

[martingrossmann]

Description

The buffer for the PageFactory loop detection buffer was not cleared over the whole test execution. In rare cases like non-parallel dataprovider tests with only one page you have to extend the Testerra property tt.page.factory.loops.

With this change the internal buffer is cleared after the method end event. Only within a method there is a default limit of 20 when you create a page of the same type in a row.

Fixes #201

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules