* guix/lint.scm (check-tests-true): New linter.
(%local-checkers)[tests-true]: Add it.
* tests/lint.scm ("tests-true: #:tests? must not be set to #t")
("tests-true: absent #:tests? is acceptable")
("tests-true: #:tests? #f is acceptable")
("tests-true: #:tests? #t acceptable when compiling natively"): Test it.
Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>