wasi-js-bindings: Basic implemention of sock_send and sock_recv

WASI's sock_send and sock_recv are very similar to fd_write and fd_read,
but with an extra flag parameter. This CL makes sock_send/sock_recv
delegate to fd_write/fd_read if no flags are passed in.

See github.com/WebAssembly/WASI/issues/4 for additional context.

Bug: b/276352391
Change-Id: I52af0213bb928fb284adf6c74521cdaf451f10fc
Reviewed-on: https://chromium-review.googlesource.com/c/apps/libapps/+/4389201
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>

wasi-js-bindings/js/syscall_entry.js

@@ -851,13 +851,20 @@ export class WasiPreview1 extends Base {
   }
 
   /** @override */
-  sys_sock_recv(fd, ri_data, ri_flags, ro_datalen_ptr, ro_flags_ptr) {
-    return WASI.errno.ENOSYS;
+  sys_sock_recv(fd, ri_data_ptr, ri_data_len, ri_flags, ro_datalen_ptr,
+                ro_flags_ptr) {
+    if (ri_flags !== 0) {
+      return WASI.errno.ENOTSUP;
+    }
+    return this.sys_fd_read(fd, ri_data_ptr, ri_data_len, ro_datalen_ptr);
   }
 
   /** @override */
-  sys_sock_send(fd, si_data, si_flags, so_datalen_ptr) {
-    return WASI.errno.ENOSYS;
+  sys_sock_send(fd, si_data_ptr, si_data_len, si_flags, so_datalen_ptr) {
+    if (si_flags !== 0) {
+      return WASI.errno.ENOTSUP;
+    }
+    return this.sys_fd_write(fd, si_data_ptr, si_data_len, so_datalen_ptr);
   }
 
   /** @override */