Add UnzipMercurial to Compile for dev unit tests

UnzipMercurial is needed to be able to run the unit tests.
Test in build.win.proj is for TeamCity.  So we need to
run UnzipMercurial for Compile as well as Test.  Eventually,
we should get Test to work on dev machines as well.

Change-Id: Ibaade472de8e7a24d3233fb98b56abe28d2ff263