WasmI64AtomicWait checked alignment at 32 bit instead of 64 bit.

Bug=v8:8075

Change-Id: Ibd668ad8440e928d14a1fcae1577c4aae345151b
Reviewed-on: https://chromium-review.googlesource.com/c/1475918Reviewed-by: Ben Smith <binji@chromium.org>
Commit-Queue: Aseem Garg <aseemgarg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59713}