Also remove obsolete android ndk copy from //third_party/android_tools/ndk

Change-Id: Ief8b39d65fa82597f9f96052235923b826bd3348
Reviewed-on: https://chromium-review.googlesource.com/c/1307614Reviewed-by: Patrik Höglund <phoglund@chromium.org>
Commit-Queue: Oleh Prypin <oprypin@chromium.org>