Fix for Mantis #23909.

gvector.pp, TVector.TVectorEnumerator:
  * the size of a vector is of type SizeUInt which is LongWord on 32 bit systems and QWord on 64 bit systems and which is in both cases not the same as Integer which is LongInt
  + add a boolean property to detect whether the first call to MoveNext was done
  * check in MoveNext whether the first call was done and return approbiate results
gvector.pp, TVector:
  + declare GetEnumerator as inline as well


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@23645 3ad0048d-3df7-0310-abae-a5850022a9f2