[Interpreter] Avoid allocating pairs array in VisitDeclarations.

src/interpreter/bytecode-array-writer.cc

 // Copyright 2015 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/interpreter/bytecode-array-writer.h"
 
 #include "src/api.h"
 #include "src/interpreter/bytecode-label.h"
 #include "src/interpreter/bytecode-register.h"
 #include "src/interpreter/constant-array-builder.h"
@@ skipping 351 matching lines @@
   } else {
     // The label has not yet been bound so this is a forward reference
     // that will be patched when the label is bound. We create a
     // reservation in the constant pool so the jump can be patched
     // when the label is bound. The reservation means the maximum size
     // of the operand for the constant is known and the jump can
     // be emitted into the bytecode stream with space for the operand.
     unbound_jumps_++;
     label->set_referrer(current_offset);
     OperandSize reserved_operand_size =
-        constant_array_builder()->CreateReservedEntry();
+        constant_array_builder()->CreateDiscardableReservedEntry();
     switch (reserved_operand_size) {
       case OperandSize::kNone:
         UNREACHABLE();
         break;
       case OperandSize::kByte:
         node->set_bytecode(node->bytecode(), k8BitJumpPlaceholder);
         break;
       case OperandSize::kShort:
         node->set_bytecode(node->bytecode(), k16BitJumpPlaceholder);
         break;
       case OperandSize::kQuad:
         node->set_bytecode(node->bytecode(), k32BitJumpPlaceholder);
         break;
     }
   }
   EmitBytecode(node);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8