Splits out AttachOuterScopeInfo from DeclarationScope::Analyze and attaches
the outer scope info after parsing has completed (when parsing on the main
thread, which is the only time we have an outer scope info) instead of
during Compiler::Analyse().

BUG=v8:5203

TBR=yangguo@chromium.org

Change-Id: Idd8d2409fb20f09a9f6bbf5cff7e6edcf90077d7
Reviewed-on: https://chromium-review.googlesource.com/605889
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47243}