Don't compute library cycle when the library is resynthesized.
Don't compute library cycle when the library is resynthesized.

As I understand, we infer all types during linking.
So, there is no reason to re-infer types.
And AFAIK ensuring type inference is the only client of library cycle
information.

With the new analysis context we link and have types for all libraries,
including the one we are resolving unit for.

Removing library cycle computation makes analysis almost 40% faster.

R=brianwilkerson@google.com, paulberry@google.com
BUG=

Review URL: https://codereview.chromium.org/2473443005 .

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