[flang][OpenMP] Fix resolve common block in data-sharing clauses

The previous resolve only creates the host associated varaibles for
common block members, but does not replace the original objects with
the new created ones. Fix it and also compute the sizes and offsets
for the host common block members if they are host associated.

Reviewed By: kiranchandramohan

Differential Revision: https://reviews.llvm.org/D127214