Fix WebSocketServer sometimes missing GET request

On Ubuntu 22.04 with Linux 6.5, it was observed that when the server
gets the SSL records containing the client handshake finished message
and the first HTTP GET request in ONE read operation, the latter SSL
record is never processed.

Commit 89eaf41 should have fixed this,
but it turned out that when SSLSocketChannel2#processHandshake() is
called from SSLSocketChannel2#write(), the second SSL record containing
the HTTP GET request is stashed away, but never retrieved, since the
calling code in WebSocketServer#doWrite() has no provisions for this,
only WebSocketServer#doRead() does.

Change SSLSocketChannel2#processHandshake() to only read from the socket
when called from SSLSocketChannel#read(), to ensure that when two SSL
records are read, the second one is processed as well.

This fixes issue TooTallNate#1418.

src/main/java/org/java_websocket/SSLSocketChannel2.java

@@ -126,7 +126,7 @@ public SSLSocketChannel2(SocketChannel channel, SSLEngine sslEngine, ExecutorSer
     createBuffers(sslEngine.getSession());
     // kick off handshake
     socketChannel.write(wrap(emptybuffer));// initializes res
-    processHandshake();
+    processHandshake(false);
   }
 
   private void consumeFutureUninterruptible(Future<?> f) {
@@ -148,7 +148,7 @@ private void consumeFutureUninterruptible(Future<?> f) {
    * This method will do whatever necessary to process the sslEngine handshake. Thats why it's
    * called both from the {@link #read(ByteBuffer)} and {@link #write(ByteBuffer)}
    **/
-  private synchronized void processHandshake() throws IOException {
+  private synchronized void processHandshake(boolean isReading) throws IOException {
     if (sslEngine.getHandshakeStatus() == HandshakeStatus.NOT_HANDSHAKING) {
       return; // since this may be called either from a reading or a writing thread and because this method is synchronized it is necessary to double check if we are still handshaking.
     }
@@ -167,7 +167,7 @@ private synchronized void processHandshake() throws IOException {
       }
     }
 
-    if (sslEngine.getHandshakeStatus() == SSLEngineResult.HandshakeStatus.NEED_UNWRAP) {
+    if (isReading && sslEngine.getHandshakeStatus() == SSLEngineResult.HandshakeStatus.NEED_UNWRAP) {
       if (!isBlocking() || readEngineResult.getStatus() == Status.BUFFER_UNDERFLOW) {
         inCrypt.compact();
         int read = socketChannel.read(inCrypt);
@@ -273,7 +273,7 @@ protected void createBuffers(SSLSession session) {
 
   public int write(ByteBuffer src) throws IOException {
     if (!isHandShakeComplete()) {
-      processHandshake();
+      processHandshake(false);
       return 0;
     }
     // assert(bufferallocations > 1); // see #190
@@ -303,10 +303,10 @@ public int read(ByteBuffer dst) throws IOException {
       if (!isHandShakeComplete()) {
         if (isBlocking()) {
           while (!isHandShakeComplete()) {
-            processHandshake();
+            processHandshake(true);
           }
         } else {
-          processHandshake();
+          processHandshake(true);
           if (!isHandShakeComplete()) {
             return 0;
           }