Improve the success rate for inline keyed store on x64...

Improve the success rate for inline keyed store on x64

Added a simple new space check on the elements fixed array which can allow
updating with other values than smis without updating the remembered set.

Also combined the positive smi and range check so that a separate smi check can be avoided when the key is known to be a smi.

This is a port of r4543.

Committed: http://code.google.com/p/v8/source/detail?r=4547

[Lasse Reichstein, 2010-04-29 12:15:47]

If its faster, LGTM.

http://codereview.chromium.org/1702013/diff/1/2
File src/ia32/macro-assembler-ia32.cc (right):

http://codereview.chromium.org/1702013/diff/1/2#newcode103
src/ia32/macro-assembler-ia32.cc:103: ASSERT(cc == equal || cc == not_equal);
Use a boolean instead of only allowing a subset of Condition. Or, preferably,
make an enum with the values INSIDE, OUTSIDE.