tests/template: Add PATH to forwarding scripts
tests/template: Add PATH to forwarding scripts

This fixes test failures for the "fail to find download program uses git
clone" and the "fail to find tar uses git clone" test cases on MSYS2 and
Cygwin, due to the fact that helper programs couldn't be found with the
`PATH`. This resulted in errors such as:

  C:/msys64/usr/lib/git-core/git-upload-pack.exe: error while loading
  shared libraries: ?: cannot open shared object file: No such file or
  directory

mbland/go-script-bash