languaget is not a messaget

Pass a message handler as an argument to several of its functions, but do not
construct a messaget object without a configured message handler as that is
deprecated.

Author: tautschnig

jbmc/src/java_bytecode/README.md

@@ -678,10 +678,10 @@ determine which loading strategy to use.
 If [lazy_methods_mode](\ref java_bytecode_languaget::lazy_methods_mode) is
 \ref java_bytecode_languaget::LAZY_METHODS_MODE_EAGER then eager loading is
 used. Under eager loading
-\ref java_bytecode_languaget::convert_single_method(const irep_idt &, symbol_table_baset &)
+\ref java_bytecode_languaget::convert_single_method(const irep_idt &, symbol_table_baset &, message_handlert &)
 is called once for each method listed in method_bytecode (described above). This
 then calls
-\ref java_bytecode_languaget::convert_single_method(const irep_idt &, symbol_table_baset &, optionalt<ci_lazy_methods_neededt>)
+\ref java_bytecode_languaget::convert_single_method(const irep_idt &, symbol_table_baset &, optionalt<ci_lazy_methods_neededt>, message_handlert &)
 without a ci_lazy_methods_neededt object, which calls
 \ref java_bytecode_convert_method, passing in the method parse tree. This in
 turn uses \ref java_bytecode_convert_methodt to turn the bytecode into symbols