Validate build.sh arguments before cleaning anything

[crummel]

It's possible to run ./build.sh with a bad argument (e.g. --run-smoke-tests vs --run-smoke-test) and have portions of your already-completed build wiped. build.sh should validate all arguments before making any changes.

[mthalman]

@crummel - There already appears to be validation of the args:

[root@336cef96bae8 dotnet]# ./build.sh --run-smoke-tests
Unrecognized argument '--run-smoke-tests'
usage: ./build.sh [options]
options:
  --clean-while-building             cleans each repo after building (reduces disk space usage)
  --online                           build using online sources
  --poison                           build with poisoning checks
  --run-smoke-test                   don't build; run smoke tests
  --use-mono-runtime                 output uses the mono runtime
  --with-packages <dir>              use the specified directory of previously-built packages
  --with-sdk <dir>                   use the SDK in the specified directory for bootstrapping
use -- to send the remaining arguments to MSBuild

[crummel]

Not sure when that got added, thanks for checking it out. I'll close this then.