[flang] Adding support of -fcoarray flang and init PRIF#151675

ktras merged 2 commits intollvm:mainllvm/llvm-project:mainfrom

SiPearl:jdp/flang/coarray_flag_prif_initSiPearl/llvm-project:jdp/flang/coarray_flag_prif_initCopy head branch name to clipboard