[WebAssembly] Write initial memory in pages not bytes

Subscribers: jfb, dschuff

Differential Revision: https://reviews.llvm.org/D32660

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301687 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed