Update cpplint.py for compatibility with Python 3 (#797)

* Define xrange() for Python 3

__xrange()__ was removed in Python 3 in favor of __range()__.  This PR ensures similar functionality on both Python 2 and Python 3.

Discovered via https://travis-ci.com/nodejs/node/builds/79706150 (#21942)


flake8 testing of https://github.com/nodejs/nan on Python 3.7.0

$ __flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics__
```
/home/travis/virtualenv/python3.7.0/lib/python3.7/site-packages/pycodestyle.py:113: FutureWarning: Possible nested set at position 1
  EXTRANEOUS_WHITESPACE_REGEX = re.compile(r'[[({] | []}),;:]')
./cpplint.py:1398:12: F821 undefined name 'xrange'
  for i in xrange(startpos, len(line)):
           ^
./cpplint.py:1627:15: F821 undefined name 'xrange'
  for line in xrange(1, min(len(lines), 11)):
              ^
./cpplint.py:1755:12: F821 undefined name 'xrange'
  for i in xrange(1, len(raw_lines) - 1):
           ^
./cpplint.py:2096:14: F821 undefined name 'xrange'
    for i in xrange(linenum - 1, self.starting_linenum, -1):
             ^
./cpplint.py:2882:26: F821 undefined name 'xrange'
    for start_linenum in xrange(linenum, clean_lines.NumLines()):
                         ^
./cpplint.py:3366:19: F821 undefined name 'xrange'
    for offset in xrange(endlinenum + 1,
                  ^
./cpplint.py:3537:14: F821 undefined name 'xrange'
    for i in xrange(start - 1, max(start - 6, 0), -1):
             ^
./cpplint.py:3665:12: F821 undefined name 'xrange'
  for i in xrange(linenum, 0, -1):
           ^
./cpplint.py:3670:16: F821 undefined name 'xrange'
      for j in xrange(linenum, clean_lines.NumLines(), 1):
               ^
./cpplint.py:4233:14: F821 undefined name 'xrange'
    for i in xrange(linenum + 1, end_line):
             ^
./cpplint.py:4361:23: F821 undefined name 'unicode'
  if isinstance(line, unicode):
                      ^
./cpplint.py:5011:12: F821 undefined name 'xrange'
  for i in xrange(linenum, max(-1, linenum - 10), -1):
           ^
./cpplint.py:5032:12: F821 undefined name 'xrange'
  for i in xrange(linenum, max(-1, linenum - 10), -1):
           ^
./cpplint.py:5048:12: F821 undefined name 'xrange'
  for i in xrange(linenum, 1, -1):
           ^
./cpplint.py:5149:20: F821 undefined name 'xrange'
          for i in xrange(startline, linenum + 1):
                   ^
./cpplint.py:5173:14: F821 undefined name 'xrange'
    for i in xrange(linenum - 1, max(0, linenum - 10), -1):
             ^
./cpplint.py:5204:14: F821 undefined name 'xrange'
    for i in xrange(2):
             ^
./cpplint.py:5366:14: F821 undefined name 'xrange'
    for i in xrange(linenum - 1, max(0, linenum - 5), -1):
             ^
./cpplint.py:5625:18: F821 undefined name 'xrange'
  for linenum in xrange(clean_lines.NumLines()):
                 ^
./cpplint.py:5781:21: F821 undefined name 'xrange'
  for start_line in xrange(linenum, min(linenum + 3, clean_lines.NumLines())):
                    ^
./cpplint.py:5796:12: F821 undefined name 'xrange'
  for i in xrange(end_line, min(end_line + 3, clean_lines.NumLines())):
           ^
./cpplint.py:6029:15: F821 undefined name 'xrange'
  for line in xrange(clean_lines.NumLines()):
              ^
22    F821 undefined name 'xrange'
22
```

* Update cpplint.py for compatibility with Python 3

From https://raw.githubusercontent.com/google/styleguide/gh-pages/cpplint/cpplint.py