swift234

[build-script] Introduce -n, --dry-run feature

If -n or --dry-run is specified in command line arguments, print the commands
that would be executed to stdout, but do not execute them.

Supported in build-script and build-toolchain.

utils/build-script -n -Rt
utils/build-script -n --preset=buildbot_incremental,tools=RA,stdlib=RA
utils/build-toolchain -n local.swift