Fix an assertion failure in the full code generator.

Fix an assertion failure in the full code generator.

We hit an assertion failure when we tried to record the AST ID of
the (shared) .arguments variable proxy more than once.  This was hit
when we had multiple calls to the same parameter in a function that
used the arguments object.  The fix is to not visit the subexpressions
of the (shared) property access expression.

BUG=1060
Committed: http://code.google.com/p/v8/source/detail?r=6404

[Kevin Millikin (Chromium), 2011-01-19 14:38:59]

The assertion failure was benign in this case, because the subexpressions
(object is a stack or context-allocated variable proxy, key is a number literal)
do not have side effects so they couldn't be targeted by deoptimization.

[Søren Thygesen Gjesse, 2011-01-19 14:49:29]

LGTM