[wasm][interpreter][cleanup] Remove redundant inline annotations

The top-level functions are already in an anonymous namespace, hence
'inline' is redundant.
Similar for the methods defined within the class declaration.

R=manoskouk@chromium.org

Bug: v8:11074
Change-Id: I84f790aa2826e4f9e9efcea7cabe75d6ea05f070
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2554605Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71369}