[WebAssembly] Add linking metatdata test coverage for wasm2yaml

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

Differential Revision: https://reviews.llvm.org/D41196

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320639 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed