Fixed the range information for string lengths.

Fixed the range information for string lengths.

Currently, this doesn't really help to generate better code,
nevertheless this is the right thing to do. When our type system(s)
are fixed, this should avoid falling back to floating point operations
in various cases.

Committed: https://crrev.com/15928708228db0e02218746c37086f58576be206
Cr-Commit-Position: refs/heads/master@{#27578}

[Sven Panne, 2015-04-02 07:52:09]

svenpanne@chromium.org changed reviewers:
+ mstarzinger@chromium.org

[Michael Starzinger, 2015-04-02 08:21:10]

LGTM.

[Sven Panne, 2015-04-02 08:31:14]

The CQ bit was checked by svenpanne@chromium.org

[commit-bot: I haz the power, 2015-04-02 08:31:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1057813002/1

[commit-bot: I haz the power, 2015-04-02 08:32:53]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-02 08:33:05]

Patchset 1 (id:??) landed as
https://crrev.com/15928708228db0e02218746c37086f58576be206
Cr-Commit-Position: refs/heads/master@{#27578}