Remove support: libfeature_support_angle.so

Remove support for ANGLE's libfeature_support_angle.so.

This also removes all of the logic related to checking the rules file,
since libfeature_support_angle.so is what parsed the JSON rules file.

Bug: 187342779
Test: make and manual verification ANGLE is loaded
Change-Id: I02ac083fb8144465b60ac0ed2738c73b31addda1