Revert "Bug 1031328 overwrite modules when the test package is the sdk"

This reverts commit e1e0ab7fb68037b9663ef0db01cafe8941489a31.
Revert "Bug 1031328 - running testpkgs from outside the sdk dir broken"

This reverts commit 1894160be00768991ca99a4f6e090f716b246780.