fix($compile): allow multiple directives on a single element even if one works with a multi-element range

The problem was in keeping the values of `attrNameStart` and `attrNameEnd` between directive loop iterations which lead to the compiler looking for multi-element ranges for any directives that happened to be in the directive list after one that was applied on a range. For instance, having a ng-repeat-start and ng-class on a single element with ng-repeat being resolved first made the compiler look for an ng-repeat-end for both ng-repeat and ng-class because the `attrNameEnd` was not reset to a falsy value before the second iteration.

Closes #4002