test: add ns and us precision case to task list

tests/parallel_test/cases.task

@@ -616,6 +616,8 @@
 ,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/rowlength64k_4.py -Q 2
 ,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/rowlength64k_4.py -Q 3
 ,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/rowlength64k_4.py -Q 4
+,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/precisionUS.py
+,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/precisionNS.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 0-others/show.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 0-others/information_schema.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 2-query/abs.py