Fix some assembler issues: The assembler was miscompiling "add" (specifically, the "add reg/mem, imm" variations). The change that caused this seems to have been made because without it, some "add"s didn't compile at all. This patch reverts the previous change, and makes sure assembler operands are remapped correctly even though the input operands auto-generated due to updating operations aren't explicitly used.

// Copyright (c) 1999-2002 by Digital Mars
// All Rights Reserved
// written by Walter Bright
// www.digitalmars.com

struct GCStats
{
    size_t poolsize;		// total size of pool
    size_t usedsize;		// bytes allocated
    size_t freeblocks;		// number of blocks marked FREE
    size_t freelistsize;		// total of memory on free lists
    size_t pageblocks;		// number of blocks marked PAGE
}