isTopTypeName function

True for the names that denote a TOP TYPE — one every value inhabits.

dynamic, Object, Object? and void. Treating them as "matches anything" keeps a comparison permissive exactly where Dart's own assignability is permissive, which matters most on annotations the interpreter can only resolve coarsely.

One predicate, because three used to disagree. SCD90 measured the question X <: <top> across the implementations of RuntimeType and found NamedRuntimeType and TypeParameter answering true for all of Object / dynamic / void, while BridgedClass answered true only for a BridgedClass named Object — false for dynamic, for void, and for every NamedRuntimeType target including Object, which is the sentinel this very file documents as how dynamic is spelled when a richer type object is unavailable. Five of six cells wrong in one implementation, right in the others. So the fix is one shared answer rather than a fourth private copy of it.

Object? is included although nothing was measured spelling it: a type whose name is literally Object? can only be the nullable top type, so admitting it cannot be wrong, and omitting it would be the next asymmetry.