Even though kSpecMaxWasmMemoryPages == WasmModule::kPageSize, the
computation {wasm::kV8MaxWasmMemoryPages *
wasm::kSpecMaxWasmMemoryPages} is semantically wrong.

R=titzer@chromium.org

Change-Id: If4a875c714f1ca3c1fc928ec79b8be8aab62e8d0
Reviewed-on: https://chromium-review.googlesource.com/850072Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50375}