[OPENMP] Fix PR46730: Fix compiler crash on taskloop over constructible loop counters.

Summary:
If the variable is constrcutible, its copy is created by calling a
constructor. Such variables are duplicated and thus, must be captured.

Reviewers: jdoerfert

Subscribers: yaxunl, guansong, cfe-commits, sstefan1, caomhin

Tags: #clang

Differential Revision: https://reviews.llvm.org/D83909

(cherry picked from commit 9840208d)