It was perhaps incorrectly not declared inline while still appearing in
the main header file and then appearing in the -inl.h. MSVC doesn't like
it being declared inline however, so just inline it directly into the
main header.

Bug: v8:8510
Change-Id: I16106b91b3b4dff31e70382f2e66aa4f42fb290b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1918249
Commit-Queue: Dan Elphick <delphick@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Auto-Submit: Dan Elphick <delphick@chromium.org>
Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64988}