All privacy_test and privacy_provider_test classes:

- Namespaced with component\privacy.
- Fixed incorrect use statements with leading backslash.
- Changed code to point to global scope when needed.
- Renamed a few files to make all be privacy_test or privacy_provider_test.php
- All them passing individually.
- Complete runs passing too.

Creates a new method reset_caches() in grade_helper which resets
all static caches within this class. This is required for unit
testing.

Deprecates the function select_in_gradebook_tabs() in behat_grade.php.
After the tertiary navigation changes in gradebook this function became
obsolete and is now replaced by select_in_gradebook_navigation_selector().

The behat definition step which is used for navigating to a specific
page in the course gradebook has been updated to reflect the changes
related to the addition of tertiary navitaion in gradebook.

The $CFG->grade_navmethod setting has been removed because it is not
required anymore. This setting was used to set the type of navigation
(tabs or dropdown box) which will be used in gradebook. However, these
navigation methods are no longer used and replaced with tertiary
navigation.

The functions grade_print_tabs() and print_grade_plugin_selector()
can be deprecated as they are no longer used. These functions were
used to generate and output the tabs and dropdown box navigation
in gradebook which is now replaced with tertiary navigation.