tests 1334 to 1363 revisited.

Add a postcheck section to verify unintended file creation.

Remove needless <file> checks in verify section. Renumbering where appropriate.

tests/libtest/notexists.pl

@@ -0,0 +1,15 @@
+#!/usr/bin/env perl
+# Check that given arguments do not exist on filesystem.
+my $code = 0;
+if ($#ARGV < 0) {
+    print "Usage: $0 file1 [fileN]\n";
+    exit 2;
+}
+while (@ARGV) {
+    my $fname = shift @ARGV;
+    if (-e $fname) {
+        print "Found '$fname' when not supposed to exist.\n";
+        $code = 1;
+    }
+}
+exit $code;