This patch:
  - Refactors Parser::ParseVariableDeclarations
  - Introduces Parser::PatternMatcher class
  - Implements matching a single variable pattern
  - Implements rudimentary matching against object literal pattern
    as a proof of concept

R=arv@chromium.org,rossberg@chromium.org
BUG=v8:811
LOG=N

Review URL: https://codereview.chromium.org/1130623004

Cr-Commit-Position: refs/heads/master@{#28345}