(PUP-3011) Accept. tests - 3.7 PMT updates install

This commit adds additional acceptance test coverage for updates
to the puppet module install command. These tests validate the
following:

* (PUP-2078) Install with force should not reinstall dependencies
* (PUP-2912) Installing a module containing a symlink should
  succeed but warn about the symlink.
Seems like PMT should warn whenever it tries to extract a module containing symlinks when the host OS doesn't support them. But currently the test is skipped on Windows and Solaris...