[InstCombine] Fold binop of `select` and cast of `select` condition

[InstCombine] Fold binop of `select` and cast of `select` condition

Simplify binary operations, whose operands involve a `select`
instruction and a cast of the `select` condition. Specifically,
the binop is canonicalized into a `select` with folded arguments
as follows:

(Binop (zext C), (select C, T, F))
  -> (select C, (binop 1, T), (binop 0, F))

(Binop (sext C), (select C, T, F))
  -> (select C, (binop -1, T), (binop 0, F))

Proofs: https://alive2.llvm.org/ce/z/c_JwwM

Differential Revision: https://reviews.llvm.org/D153963