traces: don't print the stack before the gotos

The C, C++ and D skeletons used to show the stack right after popping
the stack during the reduction.  Now that the stack is printed after
reaching a new state, that has become useless:

    Entering state 1
    Stack now 0 1
    Reducing stack by rule 5 (line 83):
       $1 = token "number" (1)
    -> $$ = nterm exp (1)
    Stack now 0
    Entering state 8
    Stack now 0 8

Remove the "Stack now 0" line.

* data/skeletons/lalr1.cc, data/skeletons/lalr1.d,
* data/skeletons/lalr1.java, data/skeletons/yacc.c:
Here.

tests/calc.at

@@ -922,7 +922,7 @@ _AT_CHECK_CALC([$1],
 2^2^3 = 256
 (2^2)^3 = 64],
 [[final: 64 12 0]],
-               [1111])
+               [1017])
 
 # Some syntax errors.
 _AT_CHECK_CALC_ERROR([$1], [1], [1 2],