test_vector_test: remove unused resize_clips_ member

This was missed in:
 508ef2a6e test_vector_test: rm ref to VPX_CODEC_USE_FRAME_THREADING

The resize test vectors are already a part of `kVP9TestVectors[]`.

Change-Id: I77135821424b1f7d818746be1df38450184365a6
1 file changed