[turbofan] Reland^3 "Polymorphic inlining - try merge map check dispatch with function call dispatch."

This reverts commit ae28e0cf.

Bug: chromium:758096
Change-Id: I6541bd1ba46cd5dfb942ed3f3d382e047fb1f3e6
Reviewed-on: https://chromium-review.googlesource.com/657401Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47934}