This is a followup to 1328c4cca5, which
led to failures for tests that were not prepared to cope with that.
* tests/guix-environment-container.sh (hello_drv_nested): Pass “-E
GUIX_BUILD_OPTIONS” so ‘--no-grafts’ is passed.
* tests/guix-pack.sh (GUIX_BUILD_OPTIONS): Add ‘--no-grafts’.
* tests/transformations.scm ("options->transformation, with-graft"):
Skip when ‘glibc-final’ has a replacement.
Change-Id: Ia65c9aeb06f524252815b8290a5ca7bf97ee8136