Fix issue with skipping global object during lookup through...

Fix issue with skipping global object during lookup through
the prototype chain. In case we're skipping a global object,
we have to be careful not to use ICs for the load, because
it's possible to introduce variables on the global object
without a map change.

Committed: http://code.google.com/p/v8/source/detail?r=2385

[bak, 2009-07-08 07:09:50]

LGTM,
  Lars

http://codereview.chromium.org/149316/diff/1/2
File test/mjsunit/global-deleted-property-ic.js (right):

http://codereview.chromium.org/149316/diff/1/2#newcode32
Line 32: assertEquals(42, LoadX(this));
How about:
   for(var i = 0; i < 3; i++) assertEquals(....)