[co19] LibTest/convert tests enabled
[co19] LibTest/convert tests enabled

Change-Id: I2b736b394750fb745c2babdb48a8dff35c26948a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/157321
Reviewed-by: Alexander Thomas <29642742b6693024c89de8232f2e2542cf7eedf7@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