This removes python.bat and python3.bat batch wrappers from root of this
repository. This change brings Windows set up closer to unix.

depot_tools provides batch wrappers in python-bin and python2-bin
directories and user can opt in to use it by adding them to PATH.

Bug: 777069
Change-Id: Ie7571a49f940e7a69b6c18779499c39aee94d06a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2742181Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>