Buffer overflow in WASM modules in misc/wasm and cmd/link

When invoking functions from WASM modules, built using GOARCH=wasm GOOS=js, passing very large arguments can cause portions of the module to be overwritten with data from the arguments due to a buffer overflow error.

If using wasm_exec.js to execute WASM modules, users will need to replace their copy (as described in https://golang.org/wiki/WebAssembly#getting-started) after rebuilding any modules.