Move check for ACE Hash_Map in FindACE
Get rid of the check for ACE_String_Base_Const::size_type

Since we dropped ACE strings, this is no longer needed.

Also drop YarpCheckTypeSize, that diverged a lot from CMake original
file, and it is no longer used.
Get rid of YarpAceCheck

Now ACE is handled almost as any other dependency
Enable testing only when required