tests: Regenerate atlocal when running tests.

tests: Regenerate atlocal when running tests.

A previous patch fixed double rebuilds when running tests in some cases.
That patch removed dependencies from targets in tests/automake.mk that
were redundant because the "all" target already depended on them.  A
dependency on tests/atlocal was also removed in the belief that "all"
depended on tests/atlocal.  This belief was incorrect, which meant that
tests/atlocal would not get regenerated if it was removed or out of date.
This commit fixes the problem.

Reported-by: Joe Stringer <joe@ovn.org>
Fixes: a8cb456227b0 ("tests: Fix double-rebuild of testsuite for "check-valgrind" and similar.")
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Joe Stringer <joe@ovn.org>