SBC HL,rr writes its result to A instead of HL

[xusheng6]

In Z80IL.py, OP.SBC computes the subtraction at the operand size but always stores to A as one byte:

tmp = il.sub_borrow(size, lhs, rhs, il.flag("c"), flags="*")
tmp = il.set_reg(1, "A", tmp)

So ed 42 (SBC HL,BC) lifts as A = sbb.w{*}(HL, BC, flag:c) and the 16-bit result never reaches HL.

16-bit compare/subtract is common, so this silently drops pointer arithmetic — 39 sites in one test binary. Example: AND A / SBC HL,BC / LD A,(HL).