Store the full method reference of lambda method handles

The method ref can differ from the interface_type and method_type when,
e.g., local variables are used in the lambda method.

Author: svorenova

src/java_bytecode/java_bytecode_parse_tree.h

@@ -189,6 +189,7 @@ class java_bytecode_parse_treet
     public:
       method_handle_typet handle_type;
       irep_idt lambda_method_name;
+      irep_idt lambda_method_ref;
       irep_idt interface_type;
       irep_idt method_type;
       u2_valuest u2_values;

src/java_bytecode/java_bytecode_parser.cpp

@@ -1777,9 +1777,9 @@ java_bytecode_parsert::parse_method_handle(const method_handle_infot &entry)
   const name_and_type_infot &name_and_type =
     ref_entry.get_name_and_type(pool_entry_lambda);
 
-  const std::string method_name =
+  const std::string method_ref =
     class_entry.get_name(pool_entry_lambda) + "." +
-    name_and_type.get_name(pool_entry_lambda) +
+    name_and_type.get_name(pool_entry_lambda) + ':' +
     name_and_type.get_descriptor(pool_entry_lambda);
 
   lambda_method_handlet lambda_method_handle;
@@ -1792,6 +1792,7 @@ java_bytecode_parsert::parse_method_handle(const method_handle_infot &entry)
     //                "new" when it is a class variable, instantiated in <init>
     lambda_method_handle.lambda_method_name =
       name_and_type.get_name(pool_entry_lambda);
+    lambda_method_handle.lambda_method_ref = method_ref;
     lambda_method_handle.handle_type =
       method_handle_typet::LAMBDA_METHOD_HANDLE;