With the Ignition + Turbofan pipeline there is very little overlap between the data
needed for unoptimized compilation and optimized compilation. As a result, it is
cleaner to split up the CompilationInfo into UnoptimizedCompilationInfo and
OptimizedCompilationInfo.

Doing so also necessitate splitting up CompilationJob into UnoptimizedCompilationJob
and OptimizedCompilationJob - again there is not much overlap so this seems cleaner.

Change-Id: I1056ad520937b7f8582e4fc3ca8f4910742de30a
Reviewed-on: https://chromium-review.googlesource.com/995895
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52369}