Compute common supertype (regardless of whether the given set of
lower bounds contains number types, intersection types, or whatever).
If the result type S is a possibly nullable intersection X1 & ... & Xn,
N = {Xi | Xi is a primitive number type},
R = {Xi | Xi is not a primitive number type},
M = default primitive number type for {Nj},
then adjusted type T* = M & R1 & ... Rm with the same nullability as S.
NB: IntegerValueType(_) = Int & Byte & Short & Long
Dmitry Petrov
fbad16567b