inference: improve isa-constraint propagation for iskindtype objects

[aviatesk]

Currently our inference isn't able to propagate isa-based type constraint for cases like isa(Type{<:...}, DataType) since typeintersect may return Type object itself when taking Type object and iskindtype-object.

This case happens in the following kind of situation (motivated by the discussion at #46553 (comment)):

julia> function isa_kindtype(T::Type{<:AbstractVector})
           if isa(T, DataType)
               # `T` here should be inferred as `DataType` rather than `Type{<:AbstractVector}`
               return T.name.name # should be inferred as ::Symbol
           end
           return nothing
       end
isa_kindtype (generic function with 1 method)

julia> only(code_typed(isa_kindtype; optimize=false))
CodeInfo(
1 ─ %1 = (T isa Main.DataType)::Bool
└──      goto #3 if not %1
2 ─ %3 = Base.getproperty(T, :name)::Any
│   %4 = Base.getproperty(%3, :name)::Any
└──      return %4
3 ─      return Main.nothing
) => Any

This commit improves the situation by adding a special casing for abstract interpretation, rather than changing the behavior of typeintersect.

[aviatesk]

Test failures looks unrelated.