PostJob is used for wasm compilation since https://crrev.com/c/2301933,
so all platforms need to implement it.

R=ulan@chromium.org

Bug: v8:10745, chromium:1101340
Change-Id: Idf88a1305ab3f33ce3980ca7f82d4fc02b0e2443
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2315980
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69020}