message: [XLA:Python] Instantiate the platform in xla_client.initialize_platform_name.
  This is a backward compatibility measure to make JAX's existing platform fallback logic work.
diff: @@ -1796,6 +1796,9 @@ def initialize_platform_name(platform_name):
  global _default_platform_name
  _default_platform_name = platform_name
  + # Make sure the platform is valid by trying to instantiate it.
  + _get_default_local_backend()
  +
  def register_cpu_custom_call_target(name, fn):
  """Registers a CPU custom call target.
  