[deoptimizer] Preserve double bit patterns correctly.

src/arm64/deoptimizer-arm64.cc

Index: src/arm64/deoptimizer-arm64.cc
diff --git a/src/arm64/deoptimizer-arm64.cc b/src/arm64/deoptimizer-arm64.cc
index c1d04ac3fb2c26d45a55d5280f83f3d3b4a634de..0bedceb6ed8dfe653cdc3a82a370db759a37a655 100644
--- a/src/arm64/deoptimizer-arm64.cc
+++ b/src/arm64/deoptimizer-arm64.cc
@@ -78,7 +78,7 @@ void Deoptimizer::SetPlatformCompiledStubRegisters(
 
 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
   for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) {
-    double double_value = input_->GetDoubleRegister(i);
+    Float64 double_value = input_->GetDoubleRegister(i);
     output_frame->SetDoubleRegister(i, double_value);
   }
 }