ci: tweak test step

To avoid a `Makefile` dependency issue, a previous commit changed the
location of the download directory to live inside the build directory;
this change propagates that to the CI configuration. Also, it is no
longer necessary to clean up anything between runs: both the `build` and
`run` directory are subdivided by target triple so repeated builds will
not interfere.

.github/workflows/main.yml

@@ -125,17 +125,13 @@ jobs:
         export WASIP1_DIR=$(realpath $($CLANG_DIR/clang -print-resource-dir)/lib/wasip1/)
         export WASIP2_DIR=$(realpath $($CLANG_DIR/clang -print-resource-dir)/lib/wasip2/)
         mkdir -p $WASI_DIR $WASIP1_DIR $WASIP2_DIR
-        cp download/libclang_rt.builtins-wasm32.a $WASI_DIR
-        cp download/libclang_rt.builtins-wasm32.a $WASIP1_DIR
-        cp download/libclang_rt.builtins-wasm32.a $WASIP2_DIR
+        cp build/download/libclang_rt.builtins-wasm32.a $WASI_DIR
+        cp build/download/libclang_rt.builtins-wasm32.a $WASIP1_DIR
+        cp build/download/libclang_rt.builtins-wasm32.a $WASIP2_DIR
         TARGET_TRIPLE=wasm32-wasi make test
-        rm -r build
         TARGET_TRIPLE=wasm32-wasip1 make test
-        rm -r build
         TARGET_TRIPLE=wasm32-wasip2 make test
-        rm -r build
         TARGET_TRIPLE=wasm32-wasi-threads make test
-        rm -r build
         TARGET_TRIPLE=wasm32-wasip1-threads make test
       # The older version of Clang does not provide the expected symbol for the
       # test entrypoints: `undefined symbol: __main_argc_argv`.