Rename devcompiler to ddc
Rename devcompiler to ddc

The value 'devcompiler' is never being passed to this argument so this
will not break any known use cases. The name 'ddc' has better
consistency with how we label SDK platforms in `build_runner`.

Bug: https://github.com/dart-lang/build/issues/2174
Change-Id: I95f6cb75ec86c2f276298781443203d201550815
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/99704
Reviewed-by: Jake Macdonald <28dccc213a1e50b0de348b9cb82c0229ef6b65f0@google.com>
Commit-Queue: Nate Bosch <dc212c74d8afde9c690fdd09e74d3e5c5d5a3de0@google.com>

dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk