test query toolchains

Author: leonm1

.github/workflows/test.yml

@@ -315,6 +315,12 @@ jobs:
           echo "filegroup(name = \"$i\", srcs = [\"$i.wasm\"])" >> test/test_data/BUILD; \
         done
 
+    - name: Bazel query toolchains
+      shell: bash
+      run: >
+        ${{ matrix.run_under }}
+        bazel query "@llvm_toolchain//:*"
+
     - name: Bazel build/test
       shell: bash
       run: >