[OpenMP][FIX] Do check the level before return team size

The team size could/should be an ICV but since we know it is either 1 or
a value we can leave it in the team state for now. However, we still
need to determine if the current level is nested before we use it.

Reviewed By: jhuber6

Differential Revision: https://reviews.llvm.org/D111949

GitOrigin-RevId: 4c88341d17f8b81e4d21a63e0e4c16dca9063670
1 file changed