This patch adds translation from PFT to FIR for critical construct. This is part of the upstreaming effort from the fir-dev branch in [1]. [1] https://github.com/flang-compiler/f18-llvm-project Co-authored-by: kiranchandramohan <kiranchandramohan@gmail.com> Reviewed By: kiranchandramohan Differential Revision: https://reviews.llvm.org/D122218