[dartdevc] Allow multiple summaries and experiments in ddb tool
[dartdevc] Allow multiple summaries and experiments in ddb tool

This allows us to test modular compiles from the cli:

> ddb -k foo.dart
> ddb -k -s foo.dill bar.dart

Change-Id: Ib88e7ff1291a7db5ecd1774b9e594121a303f2d5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/102002
Auto-Submit: Vijay Menon <671ecbb18d31a1c038875027dcfe976af959ea9f@google.com>
Reviewed-by: Nicholas Shahan <03847abd2d8aadfe859ecb98095a31f9f515dc47@google.com>

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