This patch subsumes CoverInitializedNameProduction to create an ObjectLiteralProduction which is now used to report the duplicate proto error as well.

This patch also changes ObjectLiteralChecker::CheckProperty
to record an ObjectLiteralProduction error instead of
bailing out immediately. Once we realize that we're in a
pattern, we rewind the error, otherwise we report the
error.

BUG=v8:5121

Review-Url: https://codereview.chromium.org/2255353002
Cr-Commit-Position: refs/heads/master@{#38764}