patch 8.2.2812: Vim9: still crash when using substitute expression

Problem:    Vim9: still crash when using substitute expression.
Solution:   Put the instruction list in the stack frame. (closes #8154)

src/testdir/test_vim9_cmd.vim

@@ -1208,15 +1208,18 @@ def Test_substitute_expr()
   CheckDefFailure(['s/from/\="x"/9'], 'E488:')
 
   # When calling a function the right instruction list needs to be restored.
+  g:cond = true
   var lines =<< trim END
       vim9script
       def Foo()
           Bar([])
       enddef
       def Bar(l: list<number>)
+        if g:cond
           s/^/\=Rep()/
           for n in l[:]
           endfor
+        endif
       enddef
       def Rep(): string
           return 'rep'
@@ -1227,6 +1230,7 @@ def Test_substitute_expr()
       bwipe!
   END
   CheckScriptSuccess(lines)
+  unlet g:cond
 enddef
 
 def Test_redir_to_var()