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/toMatch.js

@@ -1,12 +1,14 @@
 getJasmineRequireObj().toMatch = function() {
 
   function toMatch() {
-    return function(actual, expected) {
-      var regexp = new RegExp(expected);
+    return {
+      compare: function(actual, expected) {
+        var regexp = new RegExp(expected);
 
-      return {
-        pass: regexp.test(actual)
-      };
+        return {
+          pass: regexp.test(actual)
+        };
+      }
     };
   }