Update run-spec-test.py
# ./run-spec-test.py --exec "../build-custom/wasm3 --repl"
#
# Running WASI verison with different engines:
-# cp wasm3.wasm ./
+# cp ../build-wasi/wasm3.wasm ./
# ./run-spec-test.py --exec "../build/wasm3 wasm3.wasm --repl"
# ./run-spec-test.py --exec "wasmtime --dir=. wasm3.wasm -- --repl"
# ./run-spec-test.py --exec "wasmer run --dir=. wasm3.wasm -- --repl"
