Make drivetrain_test_lib handle IMU transforms

This also updates the 2020 imu transform to better match the 2020
drivetrain. I haven't actually checked the yaw orientation of the IMU
though.

Change-Id: Ib036705269dfc467a60714c456751a6cfca8a67e
diff --git a/frc971/control_loops/drivetrain/BUILD b/frc971/control_loops/drivetrain/BUILD
index 9fef8f9..30abc87 100644
--- a/frc971/control_loops/drivetrain/BUILD
+++ b/frc971/control_loops/drivetrain/BUILD
@@ -691,6 +691,7 @@
         "improved_down_estimator.h",
     ],
     deps = [
+        ":drivetrain_config",
         ":drivetrain_status_fbs",
         "//aos/events:event_loop",
         "//frc971/control_loops:control_loops_fbs",
@@ -707,6 +708,7 @@
         "improved_down_estimator_test.cc",
     ],
     deps = [
+        ":drivetrain_test_lib",
         "//aos/testing:googletest",
         "//aos/testing:random_seed",
         "//frc971/control_loops/drivetrain:improved_down_estimator",