parallel-tests: redo lazy checking: recheck and RECHECK_LOGS.

parallel-tests: redo lazy checking: recheck and RECHECK_LOGS.

Replace the LAZY_TEST_SUITE API with a simpler yet more powerful
one: RECHECK_LOGS specifies those tests which are to be removed
in any case before testing.  Provide a `recheck' convenience
target to set RECHECK_LOGS to all failed and unexpectedly passed
tests.  Document several ways to limit the set of tests run.

* lib/am/check.am [PARALLEL_TESTS] (RECHECK_LOGS): New variable,
default to $(TESTS_LOGS).
(check-TESTS): Remove $(RECHECK_LOGS) not $(TEST_LOGS).  Drop use
of LAZY_TEST_SUITE.
($(TEST_SUITE_LOG)): Do not output note about lazy rerun, as
LAZY_TEST_SUITE is gone.
(recheck): New target.
(recheck-am, recheck-TESTS): New internal targets.
* doc/automake.texi (Tests): Update @vindex for TESTS and
TEST_LOGS.  Replace description of LAZY_TEST_SUITE with a list
of ways the set of tests to be run can be modified.  Document
RECHECK_LOGS and the recheck target.
* tests/defs.in: Unset RECHECK_LOGS not LAZY_TEST_SUITE.
* tests/parallel-tests.test: Adjust, replacing LAZY_TEST_SUITE
with corresponding RECHECK_LOGS settings, and add another
RECHECK_LOGS test.
* tests/parallel-tests9.test: New test, test `recheck'.
* tests/Makefile.am: Update.
Suggestion and different implementation by Akim Demaille.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>