[WebAssembly] Add version to object file metadata

Summary: See https://github.com/WebAssembly/tool-conventions/issues/54

Subscribers: jfb, dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D46069

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330969 91177308-0d34-0410-b5e6-96231b3b80d8
31 files changed