Minor performance improvements to the LookupIterator

Minor performance improvements to the LookupIterator

This change changes bootstrapping semantics for intercepted global objects. Unlike before, we'll now also call into the interceptor during bootstrapping. This affects properties loaded from within the runtime, such as global.Array and global.Symbol. The embedder will need to make sure that those values are the expected values during bootstrapping.

BUG=chromium:505998
LOG=n

Committed: https://crrev.com/5c278f632cafd0e20b960481553ece017de5da19
Cr-Commit-Position: refs/heads/master@{#29414}

[Toon Verwaest, 2015-07-01 11:49:13]

verwaest@chromium.org changed reviewers:
+ jkummerow@chromium.org

[Toon Verwaest, 2015-07-01 11:49:14]

ptal

[Jakob Kummerow, 2015-07-01 11:50:44]

lgtm

[Toon Verwaest, 2015-07-01 11:52:04]

The CQ bit was checked by verwaest@chromium.org

[commit-bot: I haz the power, 2015-07-01 11:52:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1220813005/20001

[commit-bot: I haz the power, 2015-07-01 12:20:00]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-01 12:20:23]

Patchset 2 (id:??) landed as
https://crrev.com/5c278f632cafd0e20b960481553ece017de5da19
Cr-Commit-Position: refs/heads/master@{#29414}