Use single logger for AnalyzerWorkerLoop and BuildMode instances.
Use single logger for AnalyzerWorkerLoop and BuildMode instances.

I might need to pass this instance into worker level caches, which we
will add to improve workers performance.

R=brianwilkerson@google.com
BUG=

Review-Url: https://codereview.chromium.org/2994853002 .

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