Ignore use requirement from never run code

Ignore use requirement from never run code

BUG=
R=verwaest@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=16538

[weiliang.lin2, 2013-09-04 14:04:00]

The use requirement from non-run code would lead to aggressive representation
change.
A micro to reproduce the issue as below. In the OSR entry, "start" will be
required to change from Tagged to Smi due to the non-run code (end - start)
which require SMI input.
But the change always fails because "start" is a JSDate object. This leads to
osr-deopt loop and at the end disable the function optimization for too many
opts. 
function test() {
    var start = new Date();
    var sum =0;
    for (var i = 0; i < 1e9; i += 1) {
            sum += i;
    }
    var end = new Date();
    return end - start;
}
print(test());

[Toon Verwaest, 2013-09-04 14:54:56]

LGTM. Nice catch!

[Toon Verwaest, 2013-09-04 15:25:24]

Committed patchset #1 manually as r16538 (presubmit successful).