[hal,wpilib] Rename "Test" robot mode to "Utility" (#8782)

The "Utility" name better matches its intended generic use case and
avoids overloaded terminology with unit testing (e.g. the need to name
the opmode annotation `@TestOpMode`).

The driver station will also be updated to reflect this change.

wpilibc/src/test/python/test_opmode_robot.py

@@ -73,8 +73,8 @@ def test_add_op_mode():
             )
             self.addOpMode(
                 OneArgOpMode,
-                RobotMode.TEST,
-                "OneArgOpMode-Test",
+                RobotMode.UTILITY,
+                "OneArgOpMode-Utility",
                 "Group",
                 "Description",
                 Color.WHITE,