Drop latin-1 check from BasicJsonStringifier::DoNotEscape

Drop latin-1 check from BasicJsonStringifier::DoNotEscape

R=yangguo@chromium.org
BUG=

Committed: https://code.google.com/p/v8/source/detail?r=13660

[Yang, 2013-02-13 14:44:51]

Like discussed offline, for the one-byte case

  return c >= '#' && c <= '~' && c != '\\';

and for the two-byte case

  return c >= '#' && c != '\\' && c != 0x7f;

[Yang, 2013-02-13 14:54:18]

On 2013/02/13 14:44:51, Yang wrote:
> Like discussed offline, for the one-byte case
> 
>   return c >= '#' && c <= '~' && c != '\\';
> 
> and for the two-byte case
> 
>   return c >= '#' && c != '\\' && c != 0x7f;

LGTM.