Enhance sock_addr_local syscall (#1320)

Slightly change the __wasi_sock_addr_local interface - since we already have
a `__wasi_addr_t` structure which is an union, there's no need for passing the
length around - the address buffer will always have the right length (i.e. max
of all address families).

core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/include/wasmtime_ssp.h

@@ -1007,7 +1007,7 @@ wasi_ssp_sock_addr_local(
 #if !defined(WASMTIME_SSP_STATIC_CURFDS)
     struct fd_table *curfds,
 #endif
-    __wasi_fd_t fd, uint8_t *buf, __wasi_size_t buf_len
+    __wasi_fd_t fd, __wasi_addr_t *addr
 ) __attribute__((__warn_unused_result__));
 
 __wasi_errno_t