Fixed ActionResultHolder for GCC 6

Fixed ActionResultHolder for GCC 6

Compiling with GCC 6 lead to segfaults in unit tests written using
the gmock and gtest, because it invoked undefined behavior.

When optimizing, GCC assumes the 'this' pointer can never be null.
In the ActionResultHolder template, methods returned
null pointers and it caused segfaults. These null pointers were
replaced with pointers to dynamically created pointers to the
ActionResultHolder objects.

Source of patch:
https://github.com/google/googletest/issues/705
https://github.com/google/googletest/issues/705#issuecomment-235067917

Change-Id: Id617519921a0b6bdc3df01e417d762028ec132c7