java: use full locations for diagnostics about destructors

Currently we use the syncline to report errors about a symbol's
destructor/printer.  This is not accurate (only file and line), and
this is incorrect: the file name is double quotes (a recent change,
needed to make sure we escape properly double quotes in it).  And
worst of all: with --no-line, b4_syncline expands to nothing.

Rather, push the locations into the backend, and use them.

* src/muscle-tab.h, src/muscle-tab.c (muscle_location_grow): Make it
public.
* src/output.c (prepare_symbol_definitions): Use it to pubish the
location of the printer and destructor.
* data/skeletons/lalr1.java: Use complain_at instead of complain.
* tests/java.at (Java invalid directives): Adjust expectations.
* data/skeletons/bison.m4 (b4_symbol_action_location): Remove.
We should not use b4_syncline this way.

src/output.c

@@ -478,6 +478,9 @@ prepare_symbol_definitions (void)
               SET_KEY2 (pname, "line");
               MUSCLE_INSERT_INT (key, p->location.start.line);
 
+              SET_KEY2 (pname, "loc");
+              muscle_location_grow (key, p->location);
+
               SET_KEY (pname);
               MUSCLE_INSERT_STRING_RAW (key, p->code);
             }