[DAGCombiner][X86][AArch64] Generalize A-(A&B)->A&(~B) fold (PR44448)
The fold 'A - (A & (B - 1))' -> 'A & (0 - B)'
added in 8dab0a4a7d691f2704f1079538e0ef29548db159
is too specific. It should/can just be 'A - (A & B)' -> 'A & (~B)'
Even if we don't manage to fold ~ into B,
we have likely formed ANDN node.
Also, this way there's less similar-but-duplicate folds.
Name: X - (X & Y) -> X & (~Y)
%o = and i32 %X, %Y
%r = sub i32 %X, %o
%n = xor i32 %Y, -1
%r = and i32 %X, %n