Automated cleanup which finds patterns of `Node* a = foo` where `foo` is
a TNode expression, and replaces Node* with the appropriate TNode.

Bug: v8:9396
Change-Id: I8b0cd9baf10e74d6e2e336eae62eca6cfe6a9c11
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1762515
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63335}