[Math] implement Math.random as TFJ builtin.

src/code-stub-assembler.h

 // 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.
 
 #ifndef V8_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include <functional>
 
 #include "src/compiler/code-assembler.h"
@@ skipping 280 matching lines @@
 
   // Load Float64 value by |base| + |offset| address. If the value is a double
   // hole then jump to |if_hole|. If |machine_type| is None then only the hole
   // check is generated.
   compiler::Node* LoadDoubleWithHoleCheck(
       compiler::Node* base, compiler::Node* offset, Label* if_hole,
       MachineType machine_type = MachineType::Float64());
 
   // Context manipulation
   compiler::Node* LoadContextElement(compiler::Node* context, int slot_index);
+  compiler::Node* StoreContextElement(compiler::Node* context, int slot_index,
+                                      compiler::Node* value);
   compiler::Node* LoadNativeContext(compiler::Node* context);
 
   compiler::Node* LoadJSArrayElementsMap(ElementsKind kind,
                                          compiler::Node* native_context);
 
   // Store the floating point value of a HeapNumber.
   compiler::Node* StoreHeapNumberValue(compiler::Node* object,
                                        compiler::Node* value);
   // Store a field to an object on the heap.
   compiler::Node* StoreObjectField(
@@ skipping 645 matching lines @@
                                            Label* bailout);
 
   static const int kElementLoopUnrollThreshold = 8;
 };
 
 DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_CODE_STUB_ASSEMBLER_H_