Revert of [wasm] Update {i32,i64}.const to use signed leb128 (patchset #3 id:40001 of https://codereview.chromium.org/1765673002/ )

Reason for revert:
[Sheriff] Breaks chromium win compile:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Win/builds/3844/steps/compile/logs/stdio

Original issue's description:
> [wasm] Update {i32,i64}.const to use signed leb128
>
> R=titzer@chromium.org
> R=bradnelson@chromium.org
> LOG=n
>
> Committed: https://crrev.com/4b613a67e0aa4e073946f5f0dd95ee9366c8ca86
> Cr-Commit-Position: refs/heads/master@{#34471}

TBR=bradnelson@chromium.org,titzer@chromium.org,binji@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1760363003

Cr-Commit-Position: refs/heads/master@{#34482}