[dart2js] Handle ConstantExpression in InlineWeeder.
[dart2js] Handle ConstantExpression in InlineWeeder.

With constant-update-2018 enabled, ConstantExpression nodes are added to the AST. The defaultNode() implementation increments each node count by 1 whenever we see a ConstantExpression and then does it again when we visit the child DartType, resulting in each ConstantExpression being counted twice. Instead, we should just increment the node counts when we see a ConstantExpression and not visit the children.

Change-Id: Ifdbda2913420eea1463790cab2e477e7552d1394
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/106727
Reviewed-by: Johnni Winther <0f64ef784d57ffb064b634040f9eeba0d33d0be4@google.com>
Commit-Queue: Mayank Patke <e0355b78204b67a55a952941c68c8f1b40235938@google.com>

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