dtensor.run_on() only accept Mesh
dtensor.run_on() only accept Mesh

Removal of layout_or: the result does not ensure the tensors follow layout,
passing in a Layout is confusing.

Existing users of layout_or path can migrate to to:

  dtensor.run_on(layout.mesh)

  Also, to use the context conditionally:

  with dtensor.run_on(mesh) if mesh else contextlib.nullcontext():

PiperOrigin-RevId: 443454416

tensorflow/tensorflow,yongtang/tensorflow,karllessard/tensorflow,tensorflow/tensorflow,gautam1858/tensorflow,karllessard/tensorflow,paolodedios/tensorflow,paolodedios/tensorflow,gautam1858/tensorflow,gautam1858/tensorflow,paolodedios/tensorflow,paolodedios/tensorflow,paolodedios/tensorflow,yongtang/tensorflow,yongtang/tensorflow,tensorflow/tensorflow-pywrap_saved_model,yongtang/tensorflow,Intel-tensorflow/tensorflow,Intel-tensorflow/tensorflow,Intel-tensorflow/tensorflow,gautam1858/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow-pywrap_tf_optimizer,Intel-tensorflow/tensorflow,tensorflow/tensorflow-pywrap_saved_model,gautam1858/tensorflow,gautam1858/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow,yongtang/tensorflow,Intel-tensorflow/tensorflow,karllessard/tensorflow,Intel-tensorflow/tensorflow,paolodedios/tensorflow,karllessard/tensorflow,yongtang/tensorflow,paolodedios/tensorflow,tensorflow/tensorflow,tensorflow/tensorflow-pywrap_saved_model,karllessard/tensorflow,yongtang/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow,Intel-tensorflow/tensorflow,yongtang/tensorflow,Intel-tensorflow/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow-pywrap_saved_model,gautam1858/tensorflow,karllessard/tensorflow,tensorflow/tensorflow-pywrap_saved_model,paolodedios/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,gautam1858/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,gautam1858/tensorflow,Intel-tensorflow/tensorflow,karllessard/tensorflow,karllessard/tensorflow,tensorflow/tensorflow,tensorflow/tensorflow-pywrap_saved_model,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow-pywrap_tf_optimizer,paolodedios/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow,karllessard/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,karllessard/tensorflow,tensorflow/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,gautam1858/tensorflow,yongtang/tensorflow,tensorflow/tensorflow-pywrap_saved_model,paolodedios/tensorflow,tensorflow/tensorflow-pywrap_saved_model,tensorflow/tensorflow-pywrap_saved_model,yongtang/tensorflow,gautam1858/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow,tensorflow/tensorflow,Intel-tensorflow/tensorflow,Intel-tensorflow/tensorflow,tensorflow/tensorflow-pywrap_saved_model,paolodedios/tensorflow,tensorflow/tensorflow-pywrap_saved_model,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow-experimental_link_static_libraries_once,gautam1858/tensorflow,karllessard/tensorflow,yongtang/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow-experimental_link_static_libraries_once