Fix computation of UTC time from local time at DST change points.

Fix computation of UTC time from local time at DST change points.

This also reverts r23606, which was an incorrect fix.

BUG=v8:3116, chromium:417640, chromium:415424
LOG=Y
TEST=mjsunit/regress/regress-3116.js
R=yangguo@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=24499

[ulan, 2014-10-09 13:42:11]

ulan@chromium.org changed reviewers:
+ yangguo@chromium.org

[ulan, 2014-10-09 13:42:12]

PTAL

[Yang, 2014-10-09 13:54:34]

On 2014/10/09 13:42:12, ulan wrote:
> PTAL

lgtm.

[ulan, 2014-10-09 14:17:45]

Committed patchset #2 (id:20001) manually as 24499 (presubmit successful).

[PhistucK, 2014-10-11 08:59:08]

115     // Literally following spec here leads to incorrect time computation at
 116     // the points were we transition to and from DST.

If I understand correctly, this looks like a specification violation that should
trigger a specification change.
Did you spark a discussion at TC39?

[PhistucK, 2014-10-11 09:00:58]

phistuck@gmail.com changed reviewers:
+ phistuck@gmail.com