[WebAsembly] Update default triple in test files to wasm32-unknown-unkown. Summary: The final -wasm component has been the default for some time now. Subscribers: jfb, dschuff, jgravelle-google, eraman, aheejin, JDevlieghere, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D46342 llvm-svn: 332007 GitOrigin-RevId: a5908009cdf96ed376d73f91a8418b97057b663e