Speed up HltDecReportsFilter when using regex

The following discussion from !4593 (merged) should be addressed:

• @rmatev started a discussion:

  Maybe we can do something like is done for the functor so that we don't pay the cost of regex matching for every event.

  @sesen @nskidmor shall we merge first so that the feature is available and we implement this in a later point?

  /cc @graven

Note: one can just call the functor from the C++ code -- after all, the functor is just plain C++. No need to reimplement the same idea separately.

But the whole point is to avoid using a functor?

The point is to avoid a functor which is 'compiled' externally in the functor cache. There is nothing against calling it directly from C++, and passing it directly some regex from a property. Basically hardwire it in the algorithm, except for the constructor argument which will be a property.

(it does require the header file to be available, so some code re-packaging may be in order)

Note that with the changes in Rec!4041 (merged), which removes the literals from the code generated for the functor cache, there is no reason to avoid the functor cache -- because if only literals change, then the functor will still be found in the cache.

Thanks @graven, yes lets keep this issue open. We may revert back to the functor cache in time