add test table template

docs/run_test/test_table.md

@@ -0,0 +1,9 @@
+# Table of Test Cases
+
+See also [LISAv2
+Tests](https://github.com/microsoft/lisa/blob/master/Documents/LISAv2-TestCase-Statistics.md)
+
+| Index | LISA TestName | Priority | Platform | Category | Area  |
+| ----- | :------------ | -------: | :------: | :------: | :---: |
+
+[//]: <In the format of LISAv2 if applicable>