* tests/autotest.at (AT_CHECK_AT): Add new argument, to allow

* tests/autotest.at (AT_CHECK_AT): Add new argument, to allow
top-level tests after micro-suite has been run.   Used in...
(Debugging a successful test, Debugging script and environment),
(Debugging a failed test): ...these new tests.  The first of these
is fixed by...
* lib/autotest/general.m4 (_AT_CREATE_DEBUGGING_SCRIPT): New
macro, split out from...
(AT_INIT): ...here, so that using -d also generates a run script.
Document that -d inhibits top-level logging.
* doc/autoconf.texi (testsuite Invocation): Document that -d only
inhibits top-level logging; debug scripts are created.