Replace our home-grown BitCast with bit_cast from Chrome/Google3.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 15f4dabb4dba7b4366b1be9308c379e0510ef523..09f6ac120788666ec982a99cd509340b12080fde 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -2644,7 +2644,7 @@ OStream& HEnterInlined::PrintDataTo(OStream& os) const {  // NOLINT
 
 static bool IsInteger32(double value) {
   double roundtrip_value = static_cast<double>(static_cast<int32_t>(value));
-  return BitCast<int64_t>(roundtrip_value) == BitCast<int64_t>(value);
+  return bit_cast<int64_t>(roundtrip_value) == bit_cast<int64_t>(value);
 }