Revert "Remove unused test data files"

This reverts commit ef24980e667debd0cb8f1f26218c452bacbbe084.
diff --git a/tests/data_files/crl_md4.pem b/tests/data_files/crl_md4.pem
new file mode 100644
index 0000000..1f77dab
--- /dev/null
+++ b/tests/data_files/crl_md4.pem
@@ -0,0 +1,11 @@
+-----BEGIN X509 CRL-----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=
+-----END X509 CRL-----