In previous versions one could add e.g. a filter field for their index to
a relationship, such as 'Categories.ID' where categories is a many_many
relationship. This stopped working in the SS4 upgrade. Namespaces, whoop.
Knowing if a DataObject has a table or not is irrelevant - data is queried
out and pushed into solr all the same, whether there is a join table, a
base table, or any combination with maybe a few no-tables in between.
SomeDataClass::get() will fetch all data irrelevant of tables, that's the
point of an abstraction like SilverStripe's ORM.
Add a method to clear cached variants from SearchVariant, and a configuration flag for whether
a variant should be enabled or not. Add a FullTextSearch TestState class which will globally
disable the queuedjobs and fulltextsearch shutdown handlers during tests, and is not used to
clear cached variants on each test to prevent global state leakage.
Also removes Phockito as a test dependency.