tests: avoid creating useless files in some test directories

* tests/aclocal.test: Define `$am_create_testdir' to "empty"
before sourcing ./defs, to avoid bringing in unused auxiliary
files.  Related adjustments.
* tests/aclocal3.test: Likewise.
* tests/aclocal8.test: Likewise.
* tests/aclocal9.test: Likewise.
* tests/acloca10.test: Likewise.
* tests/acloca11.test: Likewise.
* tests/acloca12.test: Likewise.
* tests/acloca15.test: Likewise.
* tests/acloca16.test: Likewise.
* tests/acloca17.test: Likewise.
* tests/acloca18.test: Likewise.
* tests/acloca20.test: Likewise.
* tests/acloca21.test: Likewise.
* tests/acloca23.test: Likewise.
* tests/aclocal-print-acdir.test: Likewise.
* tests/ar-lib.test: Likewise.
* tests/compile.test: Likewise.
* tests/compile2.test: Likewise.
* tests/compile3.test: Likewise.
* tests/compile6.test: Likewise.
* tests/instsh2.test: Likewise.
* tests/instsh3.test: Likewise.
* tests/mdate5.test: Likewise.
* tests/mdate6.test: Likewise.
* tests/missing3.test: Likewise.
* tests/missing5.test: Likewise.
* tests/mkinst3.test: Likewise.
* tests/self-check-explicit-skips.test: Likewise.
* tests/self-check-report.test: Likewise.
* tests/self-check-sanity.test: Likewise.
* tests/tap-driver-stderr.test: Likewise.

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/aclocal8.test b/tests/aclocal8.test
index 2a1a51a82..86d0e026b 100755
--- a/tests/aclocal8.test
+++ b/tests/aclocal8.test
@@ -16,9 +16,10 @@
 
 # Make sure aclocal does not require unused macros.
 
+am_create_testdir=empty
 . ./defs || Exit 1
 
-cat >> configure.in << 'END'
+cat > configure.in << 'END'
 SOME_DEFS
 END