[csa] Add Unreachable() and use it after throw sites

src/compiler/code-assembler.h

 // 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.
 
 #ifndef V8_COMPILER_CODE_ASSEMBLER_H_
 #define V8_COMPILER_CODE_ASSEMBLER_H_
 
 #include <map>
 #include <memory>
 
@@ skipping 216 matching lines @@
   bool ToIntPtrConstant(Node* node, intptr_t& out_value);
 
   Node* Parameter(int value);
   Node* GetJSContextParameter();
   void Return(Node* value);
   void Return(Node* value1, Node* value2);
   void Return(Node* value1, Node* value2, Node* value3);
   void PopAndReturn(Node* pop, Node* value);
 
   void DebugBreak();
+  void Unreachable();
   void Comment(const char* format, ...);
 
   void Bind(Label* label);
   void Goto(Label* label);
   void GotoIf(Node* condition, Label* true_label);
   void GotoIfNot(Node* condition, Label* false_label);
   void Branch(Node* condition, Label* true_label, Label* false_label);
 
   void Switch(Node* index, Label* default_label, const int32_t* case_values,
               Label** case_labels, size_t case_count);
@@ skipping 262 matching lines @@
   CodeAssemblerCallback call_epilogue_;
 
   DISALLOW_COPY_AND_ASSIGN(CodeAssemblerState);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_CODE_ASSEMBLER_H_