A64: Relax assert in register copy ctor.

src/a64/assembler-a64.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 111 matching lines @@
   Register() {
     reg_code = 0;
     reg_size = 0;
     reg_type = CPURegister::kNoRegister;
   }
 
   Register(const CPURegister& r) {  // NOLINT(runtime/explicit)
     reg_code = r.reg_code;
     reg_size = r.reg_size;
     reg_type = r.reg_type;
-    ASSERT(IsValid());
+    ASSERT(IsValid() || IsNone());
   }
 
   bool IsValid() const {
     ASSERT(IsRegister() || IsNone());
     return IsValidRegister();
   }
 
   static Register XRegFromCode(unsigned code);
   static Register WRegFromCode(unsigned code);
 
@@ skipping 82 matching lines @@
   FPRegister() {
     reg_code = 0;
     reg_size = 0;
     reg_type = CPURegister::kNoRegister;
   }
 
   FPRegister(const CPURegister& r) {  // NOLINT(runtime/explicit)
     reg_code = r.reg_code;
     reg_size = r.reg_size;
     reg_type = r.reg_type;
-    ASSERT(IsValid());
+    ASSERT(IsValid() || IsNone());
   }
 
   bool IsValid() const {
     ASSERT(IsFPRegister() || IsNone());
     return IsValidFPRegister();
   }
 
   static FPRegister SRegFromCode(unsigned code);
   static FPRegister DRegFromCode(unsigned code);
 
@@ skipping 1803 matching lines @@
 class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) {
     assembler->CheckBuffer();
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_A64_ASSEMBLER_A64_H_