Arbitrary dim for slice (#11140)

* finish refactor

* delete impl files

* compile success

* modify slice interface used in strided_slice

* delete impl files

* fix undefined error of helper function

* finish refactor

* delete impl files

* compile success

* modify slice interface used in strided_slice

* delete impl files

* fix undefined error of helper function

* type unsupported

* remove changes in py file

* move SliceSimple function into header

* fix compiling problem

* add python test

* add python test

* change type

* compile each dim of slice seperately

* add files in tensorflow/contrib/makefile/tf_op_files.txt

* add some const

* add benchmark

* capitalize and punctuate comment

* uncollapse the for loop by Duff's device

* remove ">>>>>>>>>>"