Flang implementation for COMPILER_VERSION and COMPILER_OPTIONS intrinsics

This revision implements the Fortran intrinsic procedures COMPILER_VERSION and COMPILER_OPTIONS from the iso_fortran_env module.
To be able to set the COMPILER_OPTIONS string according to the original compiler driver invocation, a string is passed to the frontend driver using the environment variable FLANG_COMPILER_OPTIONS_STRING, for lack of a better mechanism.

Fixes #59233

Reviewed By: awarzynski

Differential Revision: https://reviews.llvm.org/D140524