[WebAssembly] MC: Use inline triple in test bitcode files

This matches the CodeGen tests and makes it a little easy
to run these from the command line manually.

Differential Revision: https://reviews.llvm.org/D42440

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323275 91177308-0d34-0410-b5e6-96231b3b80d8
17 files changed