[clang] Fix computation of number of dependencies using OpenMP iterator,

by Raul Penacoba.

The size of kmp_depend_info and the number of dependencies are computed multiplying the iterator sizes, which not right.
Now size is computed as:

itersize1*numclausedeps1 + itersize2*numclausedeps2 + ... + itersizeN*numclausedepsN

where itersizeX is the size of the iterator and numclausedepsX the number of dependencies in that depend clause.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D111045