MDEV-8481 mysql-test - main.func_crypt fails if FIPS=1

disable the test when crypt(3) doesn't work

mysql-test/include/have_crypt.inc

@@ -1,4 +1,5 @@
--- require r/have_crypt.require
-disable_query_log;
-show variables like 'have_crypt';
-enable_query_log;
+# encrypt('a') is NULL if crypt(3) is not available
+# encrypt('a') is "*0" in fips mode
+if (`select length(encrypt('a')) > 3 IS NOT TRUE`) {
+  skip No crypt(3);
+}