message: NFC: Update usage of multi-threading flags.
  The multi-threading flags have changed as the feature is on by default and not experimental.
diff: @@ -417,7 +417,7 @@ pipeline. This display mode is available in mlir-opt via
  `-pass-timing-display=list`.
  ```shell
  -$ mlir-opt foo.mlir -cse -canonicalize -lower-to-llvm -pass-timing -pass-timing-display=list
  +$ mlir-opt foo.mlir -disable-pass-threading -cse -canonicalize -lower-to-llvm -pass-timing -pass-timing-display=list
  ===-------------------------------------------------------------------------===
  ... Pass execution timing report ...
  @@ -443,7 +443,7 @@ the most time, and can also be used to identify when analyses are being
  invalidated and recomputed. This is the default display mode.
  ```shell
  -$ mlir-opt foo.mlir -cse -canonicalize -lower-to-llvm -pass-timing
  +$ mlir-opt foo.mlir -disable-pass-threading -cse -canonicalize -lower-to-llvm -pass-timing
  ===-------------------------------------------------------------------------===
  ... Pass execution timing report ...
  @@ -474,7 +474,7 @@ perceived time, or clock time, whereas the `User Time` will display the total
  cpu time.
  ```shell
  -$ mlir-opt foo.mlir -experimental-mt-pm -cse -canonicalize -lower-to-llvm -pass-timing
  +$ mlir-opt foo.mlir -cse -canonicalize -lower-to-llvm -pass-timing
  ===-------------------------------------------------------------------------===
  ... Pass execution timing report ...
  