This CL adds two new kernel tools which can answer questions about
a dill file:
* count_breakdown.dart
Enumerates the different node types in the provided dill file and
counts them.
This has proved useful in the past to e.g. see how many doubles are
included in Flutter.
* size_breakdown.dart
Gives an overview of which parts of the dill file contributes how many
bytes.
This has proved useful in the past to see that the string table gets
huge when we have many doubles (because we currently save doubles in
kernel as strings).
It also adds error handling and usage information to existing tools.
Change-Id: Ie2ce9e4b8806d5975dba8f57445705a840be3474
Reviewed-on: https://dart-review.googlesource.com/42660
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Kevin Millikin <kmillikin@google.com>