chore: add a regression test for WASI (#4822)

Currently, we only have WASM regression tests that run without WASI.
However, rust provides a WASI specific target which enables code to
special case WASI. This PR adds a basic test to cover that case.

This is an initial addition to help land tokio-rs/tokio#4716.

.github/workflows/ci.yml

@@ -48,6 +48,7 @@ jobs:
       - check-readme
       - test-hyper
       - wasm32-unknown-unknown
+      - wasm32-wasi
     steps:
       - run: exit 0
 
@@ -462,3 +463,37 @@ jobs:
       - name: test tokio
         run: wasm-pack test --node -- --features "macros sync"
         working-directory: tokio
+
+  wasm32-wasi:
+    name: wasm32-wasi
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install Rust ${{ env.rust_stable }}
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ env.rust_stable }}
+          override: true
+      - uses: Swatinem/rust-cache@v1
+
+      # Install dependencies
+      - name: Install cargo-hack
+        run: cargo install cargo-hack
+
+      - name: Install wasm32-wasi target
+        run: rustup target add wasm32-wasi
+
+      - name: Install wasmtime
+        run: cargo install wasmtime-cli
+
+      - name: Install cargo-wasi
+        run: cargo install cargo-wasi
+
+      # TODO: Expand this when full WASI support lands.
+      #   Currently, this is a bare bones regression test
+      #   for features that work today with wasi.
+
+      - name: test tests-integration --features wasi-rt
+        # TODO: this should become: `cargo hack wasi test --each-feature`
+        run: cargo wasi test --test rt_yield --features wasi-rt
+        working-directory: tests-integration