Convert inspector_protocol/roll.py to python3

Bug: v8:1306483
Change-Id: I2f1baf1374e82418c117f9126db2388b84ef46ef
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3530110Reviewed-by: Almothana Athamneh <almuthanna@chromium.org>
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79615}

third_party/inspector_protocol/roll.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Copcright 2019 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-from __future__ import print_function
 import argparse
 import sys
 import os
@@ -67,7 +66,7 @@ def RunCmd(cmd):
   (stdoutdata, stderrdata) = p.communicate()
   if p.returncode != 0:
     raise Exception('%s: exit status %d', str(cmd), p.returncode)
-  return stdoutdata
+  return stdoutdata.decode('utf-8')
 
 
 def CheckRepoIsClean(path, suffix):