rewrite ground_test, add tests for ground/1 (#2075)

tests/scryer/src_tests.rs

@@ -84,3 +84,12 @@ fn dif_tests() {
         "All tests passed",
     );
 }
+
+#[test]
+fn ground_tests() {
+    run_top_level_test_with_args(
+        &["src/tests/ground.pl", "-f", "-g", "main_quiet"],
+        "",
+        "All tests passed",
+    );
+}