tensorflow: pin cpp_std to gnu++17 am: a0724395fd

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/tensorflow/+/25386002

Change-Id: I4e34ddfc25285c73b7151c7e60bcfeabdd23c521
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>