Add tests for InstanceOf's and CheckCast's MustDoNullCheck

Change-Id: I6a2b9293d91d27193625f5c61b0b64733a0c0d82
diff --git a/test/486-checker-must-do-null-check/info.txt b/test/486-checker-must-do-null-check/info.txt
new file mode 100644
index 0000000..494ff1c
--- /dev/null
+++ b/test/486-checker-must-do-null-check/info.txt
@@ -0,0 +1 @@
+Verifies MustDoNullCheck() on InstanceOf and CheckCast