[aws-cli] #! path for python uses the Studio path

[smacfarlane]

It was discovered in #2543 that in Windows, the #! line that is generated for scripts by tools like virtualenv or ruby/bundler includes the full studio path of the studio where the package was built:

PS C:\Users\Administrator\core-plans> cat C:\hab\pkgs\core\aws-cli\1.16.153\20190507142534\Scripts\aws
#!C:\hab\studios\Users--Administrator--core-plans\hab\pkgs\core\aws-cli\1.16.153\20190507142534\Scripts\python.exe
# Copyright 2012 Amazon.com, Inc. or its affiliates. All Rights Reserved.

This is probably related to habitat-sh/habitat#6483

When that issue is resolved, we should investigate if there is any further work needed to fix tools like virtualenv, possibly in the form of helper functions.