Coverage uses the value of an execution counter to detect executed functions. However non-positive execution counter does not necessary mean that a function was never executed because we sometimes reset the counter.
Introduce additional bit on a function that is set whenever we reset positive execution counter and use this bit when generating coverage data.
Bug: https://github.com/dart-lang/sdk/issues/31326
Change-Id: I5357109603defad7e7c9415c433203f16bcf88f4
Reviewed-on: https://dart-review.googlesource.com/19760
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>