[deoptimizer] Preserve double bit patterns correctly.

src/x64/deoptimizer-x64.cc

Index: src/x64/deoptimizer-x64.cc
diff --git a/src/x64/deoptimizer-x64.cc b/src/x64/deoptimizer-x64.cc
index 9fbf69e55e874b48ff5877989bcaa8f3fbb1562e..f6fabf6e4a96d0b07b3626a77dbaf3a8748a1ec1 100644
--- a/src/x64/deoptimizer-x64.cc
+++ b/src/x64/deoptimizer-x64.cc
@@ -100,7 +100,7 @@ void Deoptimizer::SetPlatformCompiledStubRegisters(
 
 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
   for (int i = 0; i < XMMRegister::kMaxNumRegisters; ++i) {
-    double double_value = input_->GetDoubleRegister(i);
+    Float64 double_value = input_->GetDoubleRegister(i);
     output_frame->SetDoubleRegister(i, double_value);
   }
 }