The data structure isn't optimized (recording data into it takes
O(n^2) time, where n is the number of unreachable nodes in the file),
and we don't need it for normal execution anyhow.
Following the model used by CFE and dart2js, the analysis driver has a
new flag `retainDataForTesting` to control whether the test data is
gathered, so that under normal execution there is no overhead. The
testing data is stored in a new class `TestingData`; we can expand
this class in the future if we need to record other intermediate
analysis results for testing.
Change-Id: I7e79d31b9f3c9c45121dceb49094be802e4d286f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/111481
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
Paul Berry
612825900e