Revert removal of compare nesting

Since we want the user to be able to pass a negative comparison function, the extra layer of wrapping is now needed

src/core/matchers/toBe.js

@@ -1,9 +1,11 @@
 getJasmineRequireObj().toBe = function() {
   function toBe() {
-    return function(actual, expected) {
-      return {
-        pass: actual === expected
-      };
+    return {
+      compare: function(actual, expected) {
+        return {
+          pass: actual === expected
+        };
+      }
     };
   }