(This version can be built under sbcl-0.6.13 and passes
regression tests, but can't bootstrap itself.)
reenabled the structure slot accessor type declarations in
added (DECLARE (OPTIMIZE (SAFETY 0))) for !LATE-TYPE-COLD-INIT
to suppress inline structure slot accessor type checks
added some regression tests for bug #126.
noticed that bugs IR1-1, IR1-2, IR1-3, and IR1-3a are gone