[tools] Fix node update unittest.

Broke after:
https://codereview.chromium.org/2757593002

NOTRY=true
TBR=yangguo@chromium.org
BUG=v8:6091

Change-Id: Id06860ad6519966a31d768ec9608b48786397e8f
Reviewed-on: https://chromium-review.googlesource.com/467209Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44371}

tools/release/test_update_node.py

@@ -30,6 +30,7 @@ EXPECTED_GITIGNORE = """
 """
 
 EXPECTED_GIT_DIFF = """
+ create mode 100644 deps/v8/base/trace_event/common/common
  rename deps/v8/baz/{delete_me => v8_new} (100%)
  rename deps/v8/{delete_me => new/v8_new} (100%)
  create mode 100644 deps/v8/third_party/jinja2/jinja2