Remove basic support for lambda flow

java/ql/test/utils/model-generator/CaptureSourceModels.expected

@@ -1,3 +1,2 @@
-| p;Sources;true;consumeSource;(int,Consumer);;Parameter[1];remote |
 | p;Sources;true;readUrl;(URL);;ReturnValue;remote |
 | p;Sources;true;socketStream;();;ReturnValue;remote |

java/ql/test/utils/model-generator/p/Sources.java

@@ -18,8 +18,4 @@ public class Sources {
         return socket.accept().getInputStream();
     }
 
-    public void consumeSource(int port, Consumer<InputStream> consumer) throws IOException {
-        ServerSocket socket = new ServerSocket(port);
-        consumer.accept(socket.accept().getInputStream());
-    }
 }