deprecate java_is_array_type

We've got a similar (but not identical) function.  This one has no users.

Author: Daniel Kroening

jbmc/src/java_bytecode/java_utils.h

@@ -20,6 +20,7 @@ Author: Daniel Kroening, [email protected]
 
 #include <goto-programs/resolve_inherited_component.h>
 
+DEPRECATED(SINCE(2019, 6, 10, "use is_java_array_type instead"))
 bool java_is_array_type(const typet &type);
 
 /// Returns true iff the argument represents a string type (CharSequence,