[deoptimizer] Preserve double bit patterns correctly.

src/s390/deoptimizer-s390.cc

Index: src/s390/deoptimizer-s390.cc
diff --git a/src/s390/deoptimizer-s390.cc b/src/s390/deoptimizer-s390.cc
index 6ee8c742130c6d1519cf6fd7832fc2f096913fa2..46d939128aea5d5c71d7db53292ea9b4f2c59f0c 100644
--- a/src/s390/deoptimizer-s390.cc
+++ b/src/s390/deoptimizer-s390.cc
@@ -95,7 +95,7 @@ void Deoptimizer::SetPlatformCompiledStubRegisters(
 
 void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
   for (int i = 0; i < DoubleRegister::kNumRegisters; ++i) {
-    double double_value = input_->GetDoubleRegister(i);
+    Float64 double_value = input_->GetDoubleRegister(i);
     output_frame->SetDoubleRegister(i, double_value);
   }
 }