[OpenMP] Prevent emission of exception handling code when using OpenMP to offload...

[OpenMP] Prevent emission of exception handling code when using OpenMP to offload to NVIDIA devices.

Summary: For the OpenMP toolchain which offloads to NVIDIA GPUs make sure that no exception handling code is emitted.

Reviewers: arpith-jacob, sfantao, caomhin, carlo.bertolli, ABataev, Hahnfeld, hfinkel, tstellar

Reviewed By: ABataev, Hahnfeld

Subscribers: rengolin, Hahnfeld, cfe-commits

Differential Revision: https://reviews.llvm.org/D29904

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@310306 91177308-0d34-0410-b5e6-96231b3b80d8