Adding myself as an owner of test directories

Change-Id: I3d6649a2b804715cebb80b8cac881ef227738088
diff --git a/quickstep/tests/OWNERS b/quickstep/tests/OWNERS
new file mode 100644
index 0000000..046d871
--- /dev/null
+++ b/quickstep/tests/OWNERS
@@ -0,0 +1 @@
+vadimt@google.com