fix memory leak when using libc-allocator
fix memory leak when using libc-allocator

WebAssembly/sexpr-wasm-prototype,citisolo/wabt,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,WebAssembly/sexpr-wasm-prototype,WebAssembly/wabt,citisolo/wabt,citisolo/wabt,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,WebAssembly/wabt,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,WebAssembly/sexpr-wasm-prototype,WebAssembly/wabt,WebAssembly/wabt,WebAssembly/wabt