Turn on overapproximation of the weak closure

Turn on overapproximation of the weak closure

BUG=v8:3862
R=hpayer@chromium.org
LOG=y

Committed: https://crrev.com/4764b133e38f96fe4efbf7c60eaae86dccc6235a
Cr-Commit-Position: refs/heads/master@{#27265}

[jochen (gone - plz use gerrit), 2015-03-17 09:43:46]

results for octane on my machine:

                               benchmark:    score |     HEAD |      % |
===================================================+==========+========+
                                Richards:  30681.0 |  30683.6 |        |
                               DeltaBlue:  48081.2 S  46148.6 S    4.2 |
                                  Crypto:  25872.2 |  25852.6 |        |
                                RayTrace:  68837.5 |  68083.5 S    1.1 |
                             EarleyBoyer:  43538.2 |  42658.7 S    2.1 |
                                  RegExp:   5000.2 |   4948.2 |    1.1 |
                                   Splay:  16093.5 S  16366.4 S   -1.7 |
                            SplayLatency:  29001.5 S  28316.4 S    2.4 |
                            NavierStokes:  29650.2 |  29483.7 |    0.6 |
                                   PdfJS:  19641.8 |  19440.6 S    1.0 |
                                Mandreel:  26503.8 |  25966.5 S    2.1 |
                         MandreelLatency:  25830.0 |  24725.0 S    4.5 |
                                 Gameboy:  68167.8 |  66815.6 S    2.0 |
                                CodeLoad:  16543.0 S  16733.9 S   -1.1 |
                                   Box2D:  47575.8 |  47214.3 S    0.8 |
                                    zlib:  66354.8 |  66235.4 |    0.2 |
                              Typescript:  32965.5 |  31639.1 S    4.2 |
                                  Octane:  29678.2 S  29412.9 S    0.9 |
---------------------------------------------------+----------+--------+

[Hannes Payer (out of office), 2015-03-18 09:33:10]

lgtm

[jochen (gone - plz use gerrit), 2015-03-18 10:25:40]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2015-03-18 10:25:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1013133002/1

[commit-bot: I haz the power, 2015-03-18 10:36:59]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-18 10:37:07]

Patchset 1 (id:??) landed as
https://crrev.com/4764b133e38f96fe4efbf7c60eaae86dccc6235a
Cr-Commit-Position: refs/heads/master@{#27265}