Generalize the display of semantic values and locations in traces.

Generalize the display of semantic values and locations in traces.
* data/glr.c (yy_reduce_print): Fix indices (again).
* data/c++.m4 (b4_rhs_value, b4_rhs_location): Don't expect
literal integers.
* data/lalr1.cc (yyreduce_print): Rename as...
(yy_reduce_print): this.
Display values and locations.
* data/yacc.c (yy_reduce_print): Likewise.
(YY_REDUCE_PRINT): Adjust to pass the required arguments.
(yysymprint): Move higher to be visible from yy_reduce_print).
(yyparse): Adjust.
* tests/calc.at: Adjust the expected length of the traces.