[flang] Lower misc intrinsics

This patch adds lowering for couple of intrinsics:
- `btest`
- `ceiling`
- `nearest`
- `scale`

This patch is part of the upstreaming effort from fir-dev branch.

Reviewed By: jeanPerier

Differential Revision: https://reviews.llvm.org/D121885



Co-authored-by: Jean Perier <jperier@nvidia.com>
Co-authored-by: V Donaldson <vdonaldson@nvidia.com>
Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
Co-authored-by: AlexisPerry <aperry@lanl.gov>