PRESUBMIT: fix CheckPythonShebang for deletion diff

This is fix for
https://ci.chromium.org/ui/p/chromium/builders/try/chromium_presubmit/1473703/overview

Bug: 1191100
Change-Id: I6ccf95b1a293a5f9889e4acc956b31c1ede9df27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3307145
Auto-Submit: Takuto Ikuta <[email protected]>
Commit-Queue: Takuto Ikuta <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/main@{#946738}
diff --git a/PRESUBMIT_test.py b/PRESUBMIT_test.py
index 799a49fb..c4d4016 100755
--- a/PRESUBMIT_test.py
+++ b/PRESUBMIT_test.py
@@ -4064,6 +4064,7 @@
             MockFile('ash/test.py', ['#!/usr/bin/python']),
             MockFile('chrome/test.py', ['#!/usr/bin/python2']),
             MockFile('third_party/blink/test.py', ['#!/usr/bin/python3']),
+            MockFile('empty.py', []),
         ]
         errors = PRESUBMIT.CheckPythonShebang(input_api, MockOutputApi())
         self.assertEqual(3, len(errors))