Add --timing

Add --timing

- Dump per thread timing information when an isolate shuts down.

DeltaBlue(RunTime): 3654.6660583941607 us.
Timing for isolate DeltaBlue.dart$main-109078706 (from 2 threads)

Thread 0 (f68f8b40):
HandleMessage : 2163.455 ms total on stack; 940.038 ms total executing; 2114.231 ms max on stack; 930.085 ms max executing.
CompileFunction : 81.020 ms total on stack; 81.020 ms total executing; 7.745 ms max on stack; 7.745 ms max executing.
CompileOptimizedFunction : 109.817 ms total on stack; 109.817 ms total executing; 10.443 ms max on stack; 10.443 ms max executing.
CollectNewGeneration : 1032.580 ms total on stack; 1032.580 ms total executing; 7.677 ms max on stack; 7.677 ms max executing.

Thread 1 (f7419700):
InitializeIsolate : 12.121 ms total on stack; 0.418 ms total executing; 12.121 ms max on stack; 0.418 ms max executing.
ObjectStore::Init : 0.002 ms total on stack; 0.002 ms total executing; 0.002 ms max on stack; 0.002 ms max executing.
Object::Init : 0.268 ms total on stack; 0.268 ms total executing; 0.268 ms max on stack; 0.268 ms max executing.
IsolateSnapshotReader : 11.433 ms total on stack; 11.433 ms total executing; 11.433 ms max on stack; 11.433 ms max executing.
CompileFunction : 111.849 ms total on stack; 111.849 ms total executing; 10.798 ms max on stack; 10.704 ms max executing.

Totals:
HandleMessage : 2163.455 ms total on stack; 940.038 ms total executing; 2114.231 ms max on stack; 930.085 ms max executing.
CompileFunction : 192.869 ms total on stack; 192.869 ms total executing; 10.798 ms max on stack; 10.704 ms max executing.
CompileOptimizedFunction : 109.817 ms total on stack; 109.817 ms total executing; 10.443 ms max on stack; 10.443 ms max executing.
CollectNewGeneration : 1032.580 ms total on stack; 1032.580 ms total executing; 7.677 ms max on stack; 7.677 ms max executing.
InitializeIsolate : 12.121 ms total on stack; 0.418 ms total executing; 12.121 ms max on stack; 0.418 ms max executing.
ObjectStore::Init : 0.002 ms total on stack; 0.002 ms total executing; 0.002 ms max on stack; 0.002 ms max executing.
Object::Init : 0.268 ms total on stack; 0.268 ms total executing; 0.268 ms max on stack; 0.268 ms max executing.
IsolateSnapshotReader : 11.433 ms total on stack; 11.433 ms total executing; 11.433 ms max on stack; 11.433 ms max executing.

R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/fe548c4bcd1c788c289c60bf916f3455c844a69d

[Cutch, 2015-08-27 14:01:11]

johnmccutchan@google.com changed reviewers:
+ rmacnak@google.com

[rmacnak, 2015-08-27 20:07:02]

lgtm

[Cutch, 2015-09-10 16:31:21]

Committed patchset #7 (id:120001) manually as
fe548c4bcd1c788c289c60bf916f3455c844a69d (presubmit successful).