[interpreter] Move temporary register allocator into own file.

src/interpreter/bytecodes.h

Index: src/interpreter/bytecodes.h
diff --git a/src/interpreter/bytecodes.h b/src/interpreter/bytecodes.h
index 9793740bda9d3e189ec7fe965c736ba9e884f60e..87c31c2d713271c15d26148b89e7f7c58e690509 100644
--- a/src/interpreter/bytecodes.h
+++ b/src/interpreter/bytecodes.h
@@ -318,6 +318,9 @@ class Register {
   static int MaxRegisterIndex();
   static int MaxRegisterIndexForByteOperand();
 
+  // Returns an invalid register.
+  static Register invalid_value() { return Register(); }
+
   // Returns the register for the function's closure object.
   static Register function_closure();
   bool is_function_closure() const;