a couple of minor testsuite patches

[Ralf Wildenhues]

I've pushed these two simple patches to next, to eat our own dog food,
and to avoid interference from outer "make check TEST_LOGS=..." etc.

Cheers,
Ralf

    testsuite: generate $(parallel_tests) just when needed.
    
    * tests/Makefile.am (check_SCRIPTS): No need to list
    $(parallel_tests) here, they can be generated as needed during
    the test run, following our recommendation in the manual.

diff --git a/tests/Makefile.am b/tests/Makefile.am
index a7ce706..b0e1bf6 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -724,7 +724,7 @@ $(parallel_tests)
 EXTRA_DIST = ChangeLog-old gen-parallel-tests $(TESTS)
 
 # Each test case depends on defs, aclocal, and automake.
-check_SCRIPTS = defs defs-p aclocal-$(APIVERSION) automake-$(APIVERSION) 
$(parallel_tests)
+check_SCRIPTS = defs defs-p aclocal-$(APIVERSION) automake-$(APIVERSION)
 
 clean-local: check-clean-local
 

    testsuite: unset TESTS, TEST_LOGS, to avoid interference.
    
    * tests/defs.in: Unset TESTS, TEST_LOGS.

diff --git a/tests/defs.in b/tests/defs.in
index 3193eed..d44ac9f 100644
--- a/tests/defs.in
+++ b/tests/defs.in
@@ -301,6 +301,8 @@ unset V
 # need to control (and test for) in some of the tests to ensure
 # backward-compatible behavior.
 unset DISABLE_HARD_ERRORS
+unset TESTS
+unset TEST_LOGS
 unset RECHECK_LOGS
 unset VERBOSE