sb-debug:arg doesn't work in TRACE :condition

[3b]

reported by enn in #lisp:

Manual says: ":condition, :break and :print forms are evaluated in a context which mocks up the lexical environment of the called function, so that sb-debug:var and sb-debug:arg can be used. "

(defun foo (a) a)
(trace foo :condition (eql (sb-debug:arg 0) 1))
(foo 0)

=>

debugger invoked on a UNBOUND-VARIABLE in thread
#<THREAD "main thread" RUNNING {10039CE903}>:
  The variable SB-DEBUG::ARG-LIST is unbound.
...
0: ((LAMBDA ()))
1: ((LAMBDA (SB-DEBUG::FRAME) :IN SB-DEBUG::COERCE-FORM) #<unavailable argument>)
2: ((LAMBDA (SB-DEBUG::FRAME SB-DEBUG::BPT &REST SB-DEBUG::ARGS) :IN SB-DEBUG::TRACE-START-BREAKPOINT-FUN) #<SB-DI::COMPILED-FRAME SB-INT:SIMPLE-EVAL-IN-LEXENV> #<unused argument> 0)
3: (SB-DEBUG::TRACE-CALL #<SB-DEBUG::TRACE-INFO FOO> #<FUNCTION FOO> 0)
4: (SB-INT:SIMPLE-EVAL-IN-LEXENV (FOO 0) #<NULL-LEXENV>)

on sbcl 1.2.2.79 x8664 linux, but works as expected (traces only when 1 is passed to foo) on 1.1.14.49 x8664 linux and 1.1.13.24 x86 linux

[Douglas Katzman (dougk)]

broken by https://sourceforge.net/p/sbcl/sbcl/ci/c4901564467e58331fb0ad003970bbbdec6908b2

[Douglas Katzman (dougk)]

Stas fixed this in 0328ec0baa09af3eff647353593236bd50651a3b