A recent ES2016 draft spec clarification indicates that, if -0 is
passed into Array.prototype.indexOf or Array.prototype.lastIndexOf
as the starting index, and the result is found at index 0, then +0
rather than -0 should be returned. This patch ensures that V8 has
that result, which is consistent with what some other browsers
return. The patch allows a couple test262 tests to pass.

R=adamk
LOG=Y

Review URL: https://codereview.chromium.org/1729653002

Cr-Commit-Position: refs/heads/master@{#34229}