[lld][WebAssembly] Convert some lld tests to assembly
When we originally wrote these tests we didn't have a stable and
fleshed out assembly format. Now we do so we should prefer that
over llvm ir for lld tests to avoid including more part of llvm
than necessary in order to run the test.
This change converts just 30 out of about 130 test files. More to
come when I have some more time.
Differential Revision: https://reviews.llvm.org/D80361