Spanification of partition_alloc/pointers/raw_ptr_unittest.cc, etc.

This is the result of running the automatic spanification on linux and
updating code to use and pass spans where size is known. The original
patch was fully automated using script:
//tools/clang/spanify/rewrite-multiple-platforms.sh -platforms=linux
Then refined with jetski-cli and at last manually refined

Original patch: patch_15.txt

Bug: 501143531
Change-Id: Ibd6153f4d6a275e5b8c3b3fa5dae177f6a8f53b1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8360269
Reviewed-by: Stephen Nusko <nuskos@chromium.org>
Commit-Queue: Daniel Angulo <angdaniel@google.com>
Cr-Commit-Position: refs/heads/main@{#1698233}
NOKEYCHECK=True
GitOrigin-RevId: 804c07d0a5fa54c7a69fe1e7a726f03cfa89d708