Split up $PATH into $PATH1 and $PATH2

This allows us to specify before and after PATH variables for running
`make regress`.

Signed-off-by: Garrett Cooper <yanegomi@gmail.com>
Merge branch 'atf-tools-regression-convert' of github.com:/yaneurabeya/freebsd into atf-tools-regression-convert
Merge branch 'atf-tools-regression-convert' of github.com:/yaneurabeya/freebsd into atf-tools-regression-convert
Merge branch 'atf-tools-regression-convert' of github.com:/yaneurabeya/freebsd into atf-tools-regression-convert