Revert "test bulk revert 2"

This reverts commit 9a2450c2f7b8db93bb326cd948e655b4d05f6e1b.

Reason for revert: test single revert

Original change's description:
> test bulk revert 2
>
> Change-Id: Ibc911275964db984e5e4ac9594370e0715bc232b
> Reviewed-on: https://chromium-review.googlesource.com/c/playground/gerrit-cq/+/5320349
> Reviewed-by: Scott Lee <ddoman@chromium.org>

Change-Id: Ib3071da4eab4a6c56f096ff64c1a726a1e9cd7f8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/playground/gerrit-cq/+/5321619
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Yiwei Zhang <yiwzhang@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
diff --git a/hello_world.md b/hello_world.md
deleted file mode 100644
index 557db03..0000000
--- a/hello_world.md
+++ /dev/null
@@ -1 +0,0 @@
-Hello World