Bump to linter 0.1.51.
Bump to linter 0.1.51.


* `unrelated_type_equality_checks` now allows comparison between `Int64` or `Int32` and `int`
* `unnecessary_parenthesis` improved to handle cascades _in_ cascades

Change-Id: I588893132e04a706e9fc93a7a16a07005465eb1f
Reviewed-on: https://dart-review.googlesource.com/55914
Reviewed-by: Brian Wilkerson <1f7641b6b14c52b9163524ab8d9aabff80176f21@google.com>

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