[lld][WebAssembly] Do not remove name section with --strip-debug

Leave the name section in the output when using the --strip-debug
flag. This treats it more like ELF symbol tables, as the name
section has similar uses at runtime (e.g. wasm engines understand
it and it can be used for symbolization at runtime).

Fixes https://github.com/emscripten-core/emscripten/issues/14623

Differential Revision: https://reviews.llvm.org/D106728