ssl: Fix "timed out" exceptions

Incorrect error handling in send/recv would raise an OSError with
an incorrect (negative) code.

It's likely that this bug was always happening in the Pico W
implementation, which became the basis of the current shared
implementation.

Push handling of WANT_{READ,WRITE} down into mbedtls_raise_error
and use it in recv_into and send.

Tested by connecting to google.com:443, sending nothing, and trying
to read a byte:

```py
import socketpool, ssl, time, wifi
socket = socketpool.SocketPool(wifi.radio)
ctx = ssl.SSLContext()
with ctx.wrap_socket(socket.socket()) as ss:
    ss.connect(("google.com", 443))
    ss.settimeout(1)
    b = bytearray(1)
    try:
        t0 = time.monotonic()
        ss.recv_into(b)
    except Exception as ee:
        t1 = time.monotonic()
        exc = ee
        print(t1-t0)
        raise exc
```

As desired, an exception `OSError: [Errno 116] ETIMEDOUT` occurred
and the time delta value was 1.0 seconds.

(tested on pycamera)

Closes: adafruit#8988

shared-module/ssl/SSLSocket.c

@@ -71,6 +71,10 @@ STATIC NORETURN void mbedtls_raise_error(int err) {
         mp_raise_OSError(-err);
     }
 
+    if (err == MBEDTLS_ERR_SSL_WANT_WRITE || err == MBEDTLS_ERR_SSL_WANT_READ) {
+        mp_raise_OSError(MP_EWOULDBLOCK);
+    }
+
     #if defined(MBEDTLS_ERROR_C)
     // Including mbedtls_strerror takes about 1.5KB due to the error strings.
     // MBEDTLS_ERROR_C is the define used by mbedtls to conditionally include mbedtls_strerror.
@@ -271,16 +275,8 @@ mp_uint_t common_hal_ssl_sslsocket_recv_into(ssl_sslsocket_obj_t *self, uint8_t
         DEBUG_PRINT("returning %d\n", ret);
         return ret;
     }
-    if (ret == MBEDTLS_ERR_SSL_WANT_READ) {
-        ret = MP_EWOULDBLOCK;
-    } else if (ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
-        // If handshake is not finished, read attempt may end up in protocol
-        // wanting to write next handshake message. The same may happen with
-        // renegotiation.
-        ret = MP_EWOULDBLOCK;
-    }
     DEBUG_PRINT("raising errno [error case] %d\n", ret);
-    mp_raise_OSError(ret);
+    mbedtls_raise_error(ret);
 }
 
 mp_uint_t common_hal_ssl_sslsocket_send(ssl_sslsocket_obj_t *self, const uint8_t *buf, uint32_t len) {
@@ -290,16 +286,8 @@ mp_uint_t common_hal_ssl_sslsocket_send(ssl_sslsocket_obj_t *self, const uint8_t
         DEBUG_PRINT("returning %d\n", ret);
         return ret;
     }
-    if (ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
-        ret = MP_EWOULDBLOCK;
-    } else if (ret == MBEDTLS_ERR_SSL_WANT_READ) {
-        // If handshake is not finished, write attempt may end up in protocol
-        // wanting to read next handshake message. The same may happen with
-        // renegotiation.
-        ret = MP_EWOULDBLOCK;
-    }
     DEBUG_PRINT("raising errno [error case] %d\n", ret);
-    mp_raise_OSError(ret);
+    mbedtls_raise_error(ret);
 }
 
 size_t common_hal_ssl_sslsocket_bind(ssl_sslsocket_obj_t *self, const char *host, size_t hostlen, uint32_t port) {