[Flang][OpenMP][Driver][MLIR] Port fopenmp-host-ir-file-path flag and add MLIR...

[Flang][OpenMP][Driver][MLIR] Port fopenmp-host-ir-file-path flag and add MLIR module attribute to proliferate to OpenMP IR lowering

This patch ports the fopenmp-host-ir-file-path flag from Clang to Flang-new, this flag
is added by the driver to the device pass when doing two phase compilation (device + host).

This flag is then applied to the module when compiling during the OpenMP device phase.
This file can then be utilised during lowering of the OpenMP dialect to LLVM-IR, which
allows the device and host to maintain 1:1 mapping of OpenMP metadata for variables
during lowering via the OpenMPIRBuilders loadOffloadInfoMetadata facilities
(which is used for declare target and I believe target regions as well).

Reviewer: awarzynski

Differential Revision: https://reviews.llvm.org/D148038