tests: fix spurious failures caused by uses of 'configure.in'

tests: fix spurious failures caused by uses of 'configure.in'

Issue introduced by the recent merges of maint into master, and
revealed by "make maintainer-check".

* tests/aclocal-install-fail.test: Likewise.
* tests/aclocal-install-mkdir.test: Likewise.
* tests/aclocal-verbose-install.test: Likewise.
* tests/installdir.test: Likewise.
* tests/instdir-cond2.test: Likewise.
* tests/instdir-no-empty.test: Likewise.
* tests/python-pr10995.test: Likewise.
* tests/aclocal-no-install-no-mkdir.test: Likewise.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>