Revert new debug info format commits:

"[Flang] Update test to not check for tail calls on debug intrinsics" &
"Reapply#3 "[RemoveDIs] Load into new debug info format by default in LLVM (#89799)"

Recent updates to flang have added debug info generation via MLIR, a path
which currently does not support debug records. The patch that enables
debug records by default (and a small followup patch) are thus being
reverted until the MLIR path has been fixed.

This reverts commits:
  21396be8
  c5aeca73