wasi-threads: run test suite (#5907)

* wasi-threads: run test suite

This change enables the running of the wasi-threads [test suite]. It
relies on a Wasmtime CLI binary being available and runs all `*.wasm`
and `*.wat` files present in the test suite directory. The results of
each execution are compared against a JSON spec file with the same base
name as the WebAssembly module. The spec file defines the expected exit
code, e.g.

This commit does not yet build any `*.c` or `*.s` files from the test
suite. That could be done later, perhaps upstream; in the meantime, this
work is still valuable as it lays the foundation for running other WASI
tests from the in-progress [wasi-testsuite] which share the same JSON
spec infrastructure.

[test suite]: https://github.com/WebAssembly/wasi-threads/tree/main/test/testsuite
[wasi-testsuite]: https://github.com/WebAssembly/wasi-testsuite

* review: move testsuite to top-level tests

* fix: remove now-unnecessary wasi-threads test

* fix: update testsuite submodule name

* fix: ignore tests on Windows

prtest:full

* fix: `cfg_attr` syntax

prtest:full

Cargo.toml

@@ -70,6 +70,8 @@ component-macro-test = { path = "crates/misc/component-macro-test" }
 component-test-util = { workspace = true }
 bstr = "0.2.17"
 libc = "0.2.60"
+serde = "1.0"
+serde_json = "1.0"
 
 [target.'cfg(windows)'.dev-dependencies]
 windows-sys = { workspace = true, features = ["Win32_System_Memory"] }