[dart2js] Fix names for late static fields.
[dart2js] Fix names for late static fields.

Change-Id: I81e3368fa2fe321964298ec1e7034255f588faca
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136843
Reviewed-by: Sigmund Cherem <beaea8fd7d2a56555046ba4f362c8a93e3938576@google.com>
Commit-Queue: Joshua Litt <9f8daed1ab51574c9a48ffacb03e4a1adb4f880c@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk