[UNDERTOW-2133] Handle RequestTooBigException

If the request is too big, throw an excpetion to allow the connection to
be cleaned up closed properly up the call stack.

core/src/main/java/io/undertow/server/protocol/ajp/AjpServerRequestConduit.java

@@ -31,6 +31,7 @@
 import io.undertow.conduits.ConduitListener;
 import io.undertow.server.Connectors;
 import io.undertow.server.HttpServerExchange;
+import io.undertow.server.RequestTooBigException;
 import io.undertow.util.ImmediatePooledByteBuffer;
 import org.xnio.IoUtils;
 import org.xnio.channels.StreamSinkChannel;
@@ -202,6 +203,8 @@ public int read(ByteBuffer dst) throws IOException {
             }
             assert STATE_FINISHED == state;
             return -1;
+        } catch (RequestTooBigException e) {
+            throw e;
         } catch (IOException | RuntimeException e) {
             IoUtils.safeClose(exchange.getConnection());
             throw e;