In ES5, ToObject was called on elements before invoking the
.toLocaleString() method on them. ES2015 specifies that ToObject is
not called. A test262 test verifies this change. This patch
implements the new ES2015 behavior. It is verified by the test262 test
built-ins/Array/prototype/toLocaleString/primitive_this_value_getter

R=adamk

Review URL: https://codereview.chromium.org/1390893003

Cr-Commit-Position: refs/heads/master@{#31160}