make Date.parse properly handle TZ offsets...

make Date.parse properly handle TZ offsets

This makes, e.g., Date.parse("2010-08-31T22:35:36-09:00") work as
expected. Without this change, the "-9:00" timezone-offset portion
causes V8 to fail to properly parse that string into a date.
BUG=http://code.google.com/p/v8/issues/detail?id=857
TEST=Try Date.parse("2010-08-31T22:35:36-09:00") and make sure
that it gets parsed without errors and does not return NaN.

[sideshowbarker, 2010-09-08 07:12:40]

This is the first V8 patch I've ever submitted. It's a trivial change and I'm
not sure it's a complete fix. If it's not, I'd be happy to work on making it
complete. I'd also be happy to write up a test for it.

[Lasse Reichstein, 2010-09-08 07:29:30]

Thank you for the patch.

The fix seems fine, the only thing I would want for it to be complete is a
regression test. The typical place for it would be
tests/mjsunit/regression/regression-857.js (based on the the bug number). The
other files in that directory show the format.

However, before being able to accept a patch, we will need you to sign a
copyright assignment form (see http://code.google.com/p/v8/wiki/Contributing -
"The small print").
If you have already signed it, we just need to know what name it's under :)

[sideshowbarker, 2010-09-08 11:14:27]

See lint output below.  These are for existing lint nonconformances that were in
the source before I touch it (unrelated to the (one-line) change i made); but as
long as I'm touching the file, you want me to go ahead and do these lint fixes
as well?

$ gcl lint Date_parse
src/dateparser-inl.h:28:  #ifndef header guard has wrong style, please use:
SRC_DATEPARSER_INL_H_  [build/header_guard] [5]
src/dateparser-inl.h:125:  #endif line should be "#endif  //
SRC_DATEPARSER_INL_H_"  [build/header_guard] [5]
src/dateparser-inl.h:31:  Include the directory when naming .h files 
[build/include] [4]
Done processing src/dateparser-inl.h
Skipping file test/mjsunit/regress/regress-857.js
Total errors found: 3

[Lasse Reichstein, 2010-09-08 11:56:00]

LGTM

The ifndef/endif are correct for V8. I'm guessing your gcl lint uses chromium
rules (or something else).
You can lint v8 code by running tools/presubmit.py

http://codereview.chromium.org/3318017/diff/15001/16002
File test/mjsunit/regress/regress-857.js (right):

http://codereview.chromium.org/3318017/diff/15001/16002#newcode36
test/mjsunit/regress/regress-857.js:36: assertEquals(1283261736000,
Date.parse("2010-08-31T22:35:36.0+09:00"));
Looks good.
How about putting the spec-required formats (ES5 15.9.1.15) first, and then the
non-standardized ones after it?