Fix command line parsing.

Fix command line parsing.

For --min-parse-length --cache=code, SetFlagsFromCommandLine sees an
argv like this: [".../blabla/d8", "min-parse-length", NULL] It then
calls strtol(NULL, ...), which strtol dislikes.

It turns out that:
- V8::Shell::SetOptions will pick out its own arguments, and replace
  them in argv with NULL values.
- v8::internal::SetFlagsFromCommandLine is mostly aware of this.
- However, when a general v8 argument w/ parameter is followed by
  a d8 argument then this happens:
  - SetOptions parses its arguments and replaces it will NULL.
  - SetFlagsFromCommandLine tries to parse and arg w/ parameter,
    but finds a NULL in its place.
  - The parsing function for the argument receives a NULL pointer
    and doesn't like it.

Easy to fix by checking for NULL after argv.
Probably little real world effect, since this only affects v8 when
used through d8.


R=hpayer@chromium.org
BUG=401432

[Hannes Payer (out of office), 2014-08-08 13:46:43]

lgtm

[vogelheim, 2014-08-11 14:03:22]

Committed as r23005.

(I inadvertently committed w/ 'git svn dcommit' rather than 'git cl dcommit',
hence no automated message.)