[WebAssembly] Revert type of wake count in atomic.wake to i32

Summary:
We decided to revert this from i64 to i32 in Nov 28 CG meeting. Fixes
PR38632.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D51010

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@340234 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed