Adds `--report-metrics` and `--report-all-metrics`.
These options print all the Metrics objects exposed by CompilerTask.
This CL has counts and durations and adds metrics to two tasks to
demonstrate the 'framework'. More task metrics will be implemented
as needed. As we do so, we will experiment to see if it is possible
to make it easier and more efficient collect metrics.
```
$ dart2js ... --report-metrics
Info: Metrics:
type_inference.time: 1.429s
deferred_load.time: 0.424s
...
$ dart2js ... --report-all-metrics
Info: Metrics:
type_inference.time: 1.300s
type_inference.time.analyze: 0.695s
type_inference.time.refine1: 0.361s
type_inference.time.refine2: 0.175s
type_inference.count.exceededMaxChange: 5
type_inference.count.overallRefines: 90827
deferred_load.time: 0.270s
deferred_load.hunkListElements: 1
```
Change-Id: I2ba66f65af604758b0cbd71a688133cb562e32ed
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/156842
Reviewed-by: Joshua Litt <joshualitt@google.com>
Commit-Queue: Stephen Adams <sra@google.com>
Stephen Adams
588f168164