The .getStaticType results for NullLiteral and NullConstant are inconsistent. The former returns `const BottomType()` and the latter return `TypeEnvironment.nullType`.
To avoid this inconsistency and since `const BottomType()` is really the "unreachable" type, used for instance of for the type of a throw expression, the implementation is changed to consistently use the .nullType.
For this to work, getStaticTypeAsInstanceOf (and the equivalent dart2js implementation), and the `Type.fromStaticType` constructor in the VM type flow analysis have to special case the .nullType.
Change-Id: If6b806d4a39ef7b906275c43fa2089b9d140523b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98563
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Johnni Winther
4fc0e1f13d