CVE-2019-3824 ldb: Add tests for ldb_wildcard_match

CVE-2019-3824 ldb: Add tests for ldb_wildcard_match

Add cmocka tests for ldb_wildcard_match.

Running test_wildcard_match under valgrind reproduces
 CVE-2019-3824 out of bounds read in wildcard compare (bug 13773)

 valgrind --suppressions=lib/ldb/tests/ldb_match_test.valgrind\
          bin/ldb_match_test

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13773

Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
(cherry picked from commit 45b75db50f5c1a7c8c38af59a62fccee5401c845)