Don't use SmartSlice just because the receiver is an array.

Don't use SmartSlice just because the receiver is an array.

Only do so if the estimated number of elements is low compared to the
end position for the slice. This is similar to other heuristics used
for array operations that use the %GetElementKeys runtime function.

R=erik.corry@gmail.com

Committed: http://code.google.com/p/v8/source/detail?r=8184

[Erik Corry, 2011-06-06 13:26:09]

LGTM but it would be good to optimize the case where we are starting at a high
index.