Add support for sqlite_version() scalar function

testing/scalar-functions.test

@@ -430,3 +430,7 @@ do_execsql_test sign-text-non-numeric {
 do_execsql_test sign-null {
   SELECT sign(NULL);
 } {}
+
+do_execsql_test sqlite_version {
+  SELECT sqlite_version();
+} {3.46.1}