[XLA] Unify RoundTripFpToString
[XLA] Unify RoundTripFpToString

Also, move off-of the TensorFlow implementation of float->string conversion.

PiperOrigin-RevId: 424733695
Change-Id: Ie9efce205718705551d7bb0673a7f757b9286362

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