Use the correct value offset for Float64x2 on ARM

runtime/vm/intermediate_language_arm.cc

Index: runtime/vm/intermediate_language_arm.cc
diff --git a/runtime/vm/intermediate_language_arm.cc b/runtime/vm/intermediate_language_arm.cc
index 499e1612f2fad4bab1768f8ba6dd2515529fb8aa..0de228e8ae8330d4b1a082e18bfbccc5c3e89232 100644
--- a/runtime/vm/intermediate_language_arm.cc
+++ b/runtime/vm/intermediate_language_arm.cc
@@ -3096,9 +3096,9 @@ void BoxFloat64x2Instr::EmitNativeCode(FlowGraphCompiler* compiler) {
   __ Bind(slow_path->exit_label());
 
   __ StoreDToOffset(value_even, out_reg,
-      Float32x4::value_offset() - kHeapObjectTag);
+      Float64x2::value_offset() - kHeapObjectTag);
   __ StoreDToOffset(value_odd, out_reg,
-      Float32x4::value_offset() + 2 * kWordSize - kHeapObjectTag);
+      Float64x2::value_offset() + 2 * kWordSize - kHeapObjectTag);
 }