Reland of https://chromium-review.googlesource.com/c/544888/.

Instead of counting profiler ticks on the shared function info (which is
shared between native contexts), count them on the feedback vector
(which is not). This allows us to continue pushing optimization
decisions off the SFI, onto the feedback vector.

Note that a side-effect of this is that ICs don't have to walk the stack
to reset profiler ticks, as they can access the feedback vector directly
from their feedback nexus.

Change-Id: I7aa6baed03f726843d1b62629c72b74f05114b48
Reviewed-on: https://chromium-review.googlesource.com/579051
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46868}