remove previous SockJS implementation, and move example to WebSocket test

javascript/ql/src/experimental/SockJS/SockJS.qll

@@ -1,46 +0,0 @@
-/**
- * Provides classes for working with [SockJS](http://sockjs.org).
- */
-
-import javascript
-
-/**
- * A model of the `SockJS` websocket data handler (https://sockjs.org).
- */
-module SockJS {
-  /**
-   * Access to user-controlled data object received from websocket
-   * For example:
-   * ```
-   * server.on('connection', function(conn) {
-   *     conn.on('data', function(message) {
-   *       ...
-   *     });
-   *  });
-   * ```
-   */
-  class SourceFromSocketJS extends RemoteFlowSource {
-    SourceFromSocketJS() {
-      exists(
-        DataFlow::CallNode createServer, DataFlow::CallNode connNode,
-        DataFlow::CallNode dataHandlerNode
-      |
-        createServer = appCreation() and
-        connNode = createServer.getAMethodCall("on") and
-        connNode.getArgument(0).getStringValue() = "connection" and
-        dataHandlerNode = connNode.getCallback(1).getParameter(0).getAMethodCall("on") and
-        dataHandlerNode.getArgument(0).getStringValue() = "data" and
-        this = dataHandlerNode.getCallback(1).getParameter(0)
-      )
-    }
-
-    override string getSourceType() { result = "input from SockJS WebSocket" }
-  }
-
-  /**
-   * Gets a new SockJS server.
-   */
-  private DataFlow::CallNode appCreation() {
-    result = DataFlow::moduleImport("sockjs").getAMemberCall("createServer")
-  }
-}