- add run line (also to package_from_installed.py while here)
- use startswith() to check if a string starts with another
- switch from optparse to argparse
  - ...and make desired-hash a required positional argument
- drop win8 sdk support (not behavior preserving, but also unused
  for years)

Bug: none
Change-Id: I73056184208a48b9d9610f330c56f3a324763195
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2679295
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>