[crankshaft] Refactor kAllowUndefinedAsNaN to kTruncatingToNumber.

src/crankshaft/ia32/lithium-codegen-ia32.cc

Index: src/crankshaft/ia32/lithium-codegen-ia32.cc
diff --git a/src/crankshaft/ia32/lithium-codegen-ia32.cc b/src/crankshaft/ia32/lithium-codegen-ia32.cc
index 86d3bb6183257c5bcdd471c33e00afcad1750d76..5424dd9204cf5159fd54669cc349f8f08d7c65e9 100644
--- a/src/crankshaft/ia32/lithium-codegen-ia32.cc
+++ b/src/crankshaft/ia32/lithium-codegen-ia32.cc
@@ -4242,8 +4242,7 @@ void LCodeGen::DoSmiUntag(LSmiUntag* instr) {
 void LCodeGen::EmitNumberUntagD(LNumberUntagD* instr, Register input_reg,
                                 Register temp_reg, XMMRegister result_reg,
                                 NumberUntagDMode mode) {
-  bool can_convert_undefined_to_nan =
-      instr->hydrogen()->can_convert_undefined_to_nan();
+  bool can_convert_undefined_to_nan = instr->truncating();
   bool deoptimize_on_minus_zero = instr->hydrogen()->deoptimize_on_minus_zero();
 
   Label convert, load_smi, done;