This CL introduces two usage counters for two CallSite functions in
sloppy mode:
  - getFunction()
  - getThis()

Chromium CL: https://crrev.com/c/1657902

Bug: v8:8742
Change-Id: I81e8fec48534f5932a72de86d9d21f3b370c66a7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1657919
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62164}