[interpreter, debugger] implement bytecode break location iterator.

test/unittests/interpreter/bytecode-array-builder-unittest.cc

 // Copyright 2014 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 "src/v8.h"
 
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/interpreter/bytecode-array-iterator.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "test/unittests/test-utils.h"
@@ skipping 376 matching lines @@
   Factory* factory = isolate()->factory();
   Handle<HeapObject> heap_num_1 = factory->NewHeapNumber(3.14);
   Handle<HeapObject> heap_num_2 = factory->NewHeapNumber(5.2);
   Handle<Object> large_smi(Smi::FromInt(0x12345678), isolate());
   Handle<HeapObject> heap_num_2_copy(*heap_num_2);
   builder.LoadLiteral(heap_num_1)
       .LoadLiteral(heap_num_2)
       .LoadLiteral(large_smi)
       .LoadLiteral(heap_num_1)
       .LoadLiteral(heap_num_1)
-      .LoadLiteral(heap_num_2_copy);
+      .LoadLiteral(heap_num_2_copy)
+      .Return();
 
   Handle<BytecodeArray> array = builder.ToBytecodeArray();
   // Should only have one entry for each identical constant.
   CHECK_EQ(array->constant_pool()->length(), 3);
 }
 
 
 TEST_F(BytecodeArrayBuilderTest, ForwardJumps) {
   static const int kFarJumpDistance = 256;
 
@@ skipping 251 matching lines @@
     iterator.Advance();
   }
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kReturn);
   iterator.Advance();
   CHECK(iterator.done());
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8