TF WhereOp now acts more like np.where: extend input types to any numeric type.

(with the exception of tf.half).

This allows one to call:
  tf.where(float_tensor)
instead of
  tf.where(tf.not_equal(float_tensor, 0))

or
  tf.where(complex_tensor)
instead of
  tf.where(tf.not_equal(tf.abs(complex_tensor), 0))

PiperOrigin-RevId: 170758184