Decodes SFI::Flags on construction and sets properties in ParseInfo::flags_ directly, as well
as adding a FunctionKind field, instead of keeping the encoded SFI flags in the ParseInfo.

BUG=v8:8041

Change-Id: I9bd9345b29a8b0e9ffb3e2e73aac11ae6ef69322
Reviewed-on: https://chromium-review.googlesource.com/1169181Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55080}