[interpreter] Compilation fix in bytecode source position tester.

test/cctest/interpreter/source-position-matcher.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "test/cctest/interpreter/source-position-matcher.h"
 
 #include "src/objects-inl.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 namespace interpreter {
 
 // Comparer for PositionTableEntry instances.
 struct PositionTableEntryComparer {
   bool operator()(const PositionTableEntry& lhs,
-                  const PositionTableEntry& rhs) {
+                  const PositionTableEntry& rhs) const {
     int lhs_type_score = type_score(lhs);
     int rhs_type_score = type_score(rhs);
     if (lhs_type_score == rhs_type_score) {
       return lhs.source_position < rhs.source_position;
     } else {
       return lhs_type_score < rhs_type_score;
     }
   }
 
-  int type_score(const PositionTableEntry& entry) {
+  int type_score(const PositionTableEntry& entry) const {
     return entry.is_statement ? 1 : 0;
   }
 };
 
 //
 // The principles for comparing source positions in bytecode arrays
 // are:
 //
 // 1. The number of statement positions must be the same in both.
 //
@@ skipping 178 matching lines @@
     positions->push_back({iterator->bytecode_offset(),
                           iterator->source_position(),
                           iterator->is_statement()});
     iterator->Advance();
   }
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8