Fix an issue where the scroll stopped working.

Under certain conditions, it was possible to get stuck in a state where any
user-initiated scroll would be met with "Working around
vector-im/vector-web#528" and overridden. Fix this by removing the duplication
between _lastSetScroll and recentEventScroll, and using _lastSetScroll which is
more reliable.

test/test-utils.js

@@ -5,6 +5,18 @@ var jssdk = require('matrix-js-sdk');
 var MatrixEvent = jssdk.MatrixEvent;
 var sinon = require('sinon');
 
+/**
+ * Perform common actions before each test case, e.g. printing the test case
+ * name to stdout.
+ * @param {Mocha.Context} context  The test context
+ */
+module.exports.beforeEach = function(context) {
+    var desc = context.currentTest.fullTitle();
+    console.log();
+    console.log(desc);
+    console.log(new Array(1 + desc.length).join("="));
+};
+
 
 /**
  * Stub out the MatrixClient, and configure the MatrixClientPeg object to
@@ -128,22 +140,3 @@ module.exports.mkMessage = function(opts) {
     };
     return module.exports.mkEvent(opts);
 };
-
-/**
- * make the test fail, with the given exception
- *
- * <p>This is useful for use with integration tests which use asyncronous
- * methods: it can be added as a 'catch' handler in a promise chain.
- *
- * @param {Error} error   exception to be reported
- *
- * @example
- * it("should not throw", function(done) {
- *    asynchronousMethod().then(function() {
- *       // some tests
- *    }).catch(utils.failTest).done(done);
- * });
- */
-module.exports.failTest = function(error) {
-    expect(error.stack).toBe(null);
-};