Revert "segfault at i386-dis.c:9815"

This reverts commit 92d450c79ad321e42f9a77692b5db10d0f7b9344.

Accessing these local var structs using a volatile qualified pointer
may indeed read the object, but I don't think changed values are
guaranteed to be written back to the object unless the actual object
is declared volatile.  That would probably slow down i386 disassembly
unacceptably.