Pull async matchers out to their own functions

- Makes AsyncExpectation closer to Expectation

src/core/matchers/async/toBeRejectedWith.js

@@ -0,0 +1,46 @@
+getJasmineRequireObj().toBeRejectedWith = function(j$) {
+  /**
+   * Expect a promise to be rejected with a value equal to the expected, using deep equality comparison.
+   * @function
+   * @async
+   * @name async-matchers#toBeRejectedWith
+   * @param {Object} expected - Value that the promise is expected to be rejected with
+   * @example
+   * await expectAsync(aPromise).toBeRejectedWith({prop: 'value'});
+   * @example
+   * return expectAsync(aPromise).toBeRejectedWith({prop: 'value'});
+   */
+  return function toBeRejectedWith(util, customEqualityTesters) {
+    return {
+      compare: function(actualPromise, expectedValue) {
+        function prefix(passed) {
+          return 'Expected a promise ' +
+            (passed ? 'not ' : '') +
+            'to be rejected with ' + j$.pp(expectedValue);
+        }
+
+        return actualPromise.then(
+          function() {
+          return {
+            pass: false,
+            message: prefix(false) + ' but it was resolved.'
+          };
+        },
+        function(actualValue) {
+          if (util.equals(actualValue, expectedValue, customEqualityTesters)) {
+            return {
+              pass: true,
+              message: prefix(true) + '.'
+            };
+          } else {
+            return {
+              pass: false,
+              message: prefix(false) + ' but it was rejected with ' + j$.pp(actualValue) + '.'
+            };
+          }
+        }
+        );
+      }
+    };
+  };
+};