In recent wasmtime, `-S` flags need to come after `run`.
Also add `-W threads=y` following the wasmtime test suite,
- fc3c868b13/tests/all/cli_tests.rs (L580-L581)
Also explicity enable the `cli` feature because this is used for CMake
try_run.
This is a different toolchain following how wasi-sdk defines the
platform triple and how builds are configured -- everything should be
built with the flags defined in the toolchain file.
We build from web-wasi:latest, and that is built first.
