Enable shared memory in wasmtime for threads SDK

The wasip1-threads SDK requires shared memory support in wasmtime.
Without the -W shared-memory=y flag, tests fail to run with:
"shared memory support is disabled for this engine"

Author: pedrovgs

scripts/build-and-test-wasm.sh

@@ -145,7 +145,7 @@ run_tests() {
     # Determine wasmtime flags based on SDK type
     WASMTIME_FLAGS="--dir ."
     if echo "$SWIFT_SDK_NAME" | grep -q "threads"; then
-        WASMTIME_FLAGS="$WASMTIME_FLAGS --wasm threads=y --wasi threads=y"
+        WASMTIME_FLAGS="$WASMTIME_FLAGS --wasm threads=y --wasi threads=y -W shared-memory=y"
     fi
 
     wasmtime run $WASMTIME_FLAGS "$TEST_BINARY"