d: prepare to be able to run LAC tests

Unfortunately it seems to be quite difficult to have "LAC: Exploratory
stack" run for D.

* data/skeletons/lalr1.d: We need File when traces are enabled.
* tests/local.at (AT_YYLEX_DEFINE(d)): New.
* tests/regression.at: Prepare for D, but don't run it, it does not
work.

data/skeletons/lalr1.d

@@ -300,6 +300,7 @@ b4_user_union_members
 ]b4_parse_param_cons[
   }
 ]b4_parse_trace_if([[
+  import std.stdio;
   private File yyDebugStream;
 
   /**