add flatten microbenchmarks
add flatten microbenchmarks

PiperOrigin-RevId: 327312373
Change-Id: I8df010e5e1768755531c80d14028463bab4c9cce

Intel-Corporation/tensorflow,davidzchen/tensorflow,petewarden/tensorflow,frreiss/tensorflow-fred,paolodedios/tensorflow,sarvex/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow,aam-at/tensorflow,davidzchen/tensorflow,annarev/tensorflow,paolodedios/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,frreiss/tensorflow-fred,Intel-Corporation/tensorflow,yongtang/tensorflow,Intel-tensorflow/tensorflow,petewarden/tensorflow,tensorflow/tensorflow-pywrap_saved_model,tensorflow/tensorflow,frreiss/tensorflow-fred,paolodedios/tensorflow,frreiss/tensorflow-fred,frreiss/tensorflow-fred,cxxgtxy/tensorflow,Intel-tensorflow/tensorflow,aldian/tensorflow,gautam1858/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow-pywrap_saved_model,frreiss/tensorflow-fred,Intel-Corporation/tensorflow,tensorflow/tensorflow,Intel-tensorflow/tensorflow,sarvex/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,karllessard/tensorflow,annarev/tensorflow,davidzchen/tensorflow,aam-at/tensorflow,yongtang/tensorflow,petewarden/tensorflow,cxxgtxy/tensorflow,paolodedios/tensorflow,Intel-Corporation/tensorflow,annarev/tensorflow,Intel-tensorflow/tensorflow,paolodedios/tensorflow,paolodedios/tensorflow,freedomtan/tensorflow,aam-at/tensorflow,karllessard/tensorflow,davidzchen/tensorflow,Intel-tensorflow/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,aam-at/tensorflow,cxxgtxy/tensorflow,gautam1858/tensorflow,Intel-Corporation/tensorflow,freedomtan/tensorflow,petewarden/tensorflow,aldian/tensorflow,Intel-tensorflow/tensorflow,tensorflow/tensorflow-pywrap_saved_model,gautam1858/tensorflow,petewarden/tensorflow,annarev/tensorflow,davidzchen/tensorflow,tensorflow/tensorflow,karllessard/tensorflow,gautam1858/tensorflow,Intel-tensorflow/tensorflow,petewarden/tensorflow,petewarden/tensorflow,Intel-Corporation/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,annarev/tensorflow,sarvex/tensorflow,Intel-tensorflow/tensorflow,Intel-tensorflow/tensorflow,gautam1858/tensorflow,annarev/tensorflow,davidzchen/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,Intel-tensorflow/tensorflow,petewarden/tensorflow,petewarden/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow,freedomtan/tensorflow,cxxgtxy/tensorflow,aldian/tensorflow,petewarden/tensorflow,yongtang/tensorflow,tensorflow/tensorflow-pywrap_saved_model,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow-pywrap_saved_model,aam-at/tensorflow,Intel-tensorflow/tensorflow,sarvex/tensorflow,yongtang/tensorflow,tensorflow/tensorflow-pywrap_saved_model,davidzchen/tensorflow,aldian/tensorflow,annarev/tensorflow,aam-at/tensorflow,paolodedios/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,davidzchen/tensorflow,annarev/tensorflow,freedomtan/tensorflow,Intel-Corporation/tensorflow,cxxgtxy/tensorflow,tensorflow/tensorflow-pywrap_saved_model,frreiss/tensorflow-fred,paolodedios/tensorflow,tensorflow/tensorflow-pywrap_saved_model,aldian/tensorflow,aam-at/tensorflow,freedomtan/tensorflow,tensorflow/tensorflow-pywrap_saved_model,frreiss/tensorflow-fred,tensorflow/tensorflow-pywrap_saved_model,freedomtan/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,karllessard/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,frreiss/tensorflow-fred,karllessard/tensorflow,freedomtan/tensorflow,aam-at/tensorflow,tensorflow/tensorflow,sarvex/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,aam-at/tensorflow,freedomtan/tensorflow,davidzchen/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,cxxgtxy/tensorflow,sarvex/tensorflow,karllessard/tensorflow,gautam1858/tensorflow,karllessard/tensorflow,davidzchen/tensorflow,frreiss/tensorflow-fred,paolodedios/tensorflow,paolodedios/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,karllessard/tensorflow,gautam1858/tensorflow,cxxgtxy/tensorflow,petewarden/tensorflow,yongtang/tensorflow,tensorflow/tensorflow,gautam1858/tensorflow,davidzchen/tensorflow,aam-at/tensorflow,gautam1858/tensorflow,tensorflow/tensorflow,paolodedios/tensorflow,sarvex/tensorflow,freedomtan/tensorflow,Intel-Corporation/tensorflow,tensorflow/tensorflow-pywrap_saved_model,aldian/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,sarvex/tensorflow,yongtang/tensorflow,yongtang/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,tensorflow/tensorflow-pywrap_tf_optimizer,freedomtan/tensorflow,annarev/tensorflow,frreiss/tensorflow-fred,cxxgtxy/tensorflow,tensorflow/tensorflow,aldian/tensorflow,gautam1858/tensorflow,yongtang/tensorflow,aldian/tensorflow,aam-at/tensorflow,yongtang/tensorflow,yongtang/tensorflow,karllessard/tensorflow,annarev/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,davidzchen/tensorflow,karllessard/tensorflow,tensorflow/tensorflow,gautam1858/tensorflow,freedomtan/tensorflow,frreiss/tensorflow-fred,tensorflow/tensorflow-experimental_link_static_libraries_once,aam-at/tensorflow,karllessard/tensorflow,tensorflow/tensorflow,annarev/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,yongtang/tensorflow,gautam1858/tensorflow,petewarden/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,freedomtan/tensorflow