Update to wasi-sdk 27, for test compilation

Also, pass --target=wasm32-wasip1 to build.sh, given that the existing
tests target that version.

Author: wingo

.github/workflows/compile-tests.yml

@@ -82,7 +82,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest, windows-11-arm]
     env:
-      WASI_VERSION: 17
+      WASI_VERSION: 27
     steps:
       - name: Check out repository code
         uses: actions/checkout@v3

tests/c/build.sh

@@ -8,6 +8,6 @@ for input in testsuite/*.c; do
 
   if [ "$input" -nt "$output" ]; then
     echo "Compiling $input"
-    $CC "$input" -o "$output"
+    $CC --target=wasm32-wasip1 "$input" -o "$output"
   fi
 done