message: [XLA:Python] Don't use a finalizer in Buffer.
  The C++-based implementations of c_buffer implementations already know how to delete their device-side buffers on destruction. So the use of a __del__() method is superfluous, and also turns out to be slow.
diff: @@ -68,7 +68,7 @@ class Backend(object):
  """Allocates buffers and populates them with `pyvals`."""
  return [
  self.buffer_from_pyval(pyval, device)
  - for pyval, device in zip(pyvals_and_devices)
  + for pyval, device in pyvals_and_devices
  ]
  @abc.abstractmethod
  @@ -349,9 +349,6 @@ class Buffer(object):
  def is_deleted(self):
  return self.c_buffer is None
  - def __del__(self):
  - self.delete()
  -
  # TODO(phawkins): Alias for backward compatibility. Remove after JAX drops
  # compatibility with Jaxlib versions older than 0.1.13.
  