Don't check for equality in move assignment

Assume it is undefined behavior to move-assing value to itself.

components/detournavigator/navmeshtilescache.hpp

@@ -69,9 +69,6 @@ namespace DetourNavigator
 
             Value& operator =(Value&& other)
             {
-                if (mIterator == other.mIterator)
-                    return *this;
-
                 if (mIterator != ItemIterator())
                     mOwner->releaseItem(mIterator);