Clean up HermesValue::getNativeValue

Summary:
This function doesn't really serve a purpose, particularly now that
`NativeValue`s can only be one thing.

Reviewed By: kodafb

Differential Revision: D29872075

fbshipit-source-id: 3cee34da4024170828d0d1eecda6313df21638ee

include/hermes/VM/HermesValue.h

@@ -394,13 +394,6 @@ class HermesValue {
     return safeTypeCast<uint64_t, double>(raw_);
   }
 
-  inline int64_t getNativeValue() const {
-    assert(isNativeValue());
-    // Sign-extend the value.
-    return (static_cast<int64_t>(raw_ & kDataMask) << (64 - kNumDataBits)) >>
-        (64 - kNumDataBits);
-  }
-
   inline uint32_t getNativeUInt32() const {
     assert(isNativeValue());
     return (uint32_t)raw_;

lib/VM/HermesValue.cpp

@@ -50,7 +50,7 @@ llvh::raw_ostream &operator<<(llvh::raw_ostream &OS, HermesValue hv) {
       return OS << ']';
     }
     case NativeValueTag:
-      return OS << "[NativeValue " << hv.getNativeValue() << "]";
+      return OS << "[NativeValue " << hv.getNativeUInt32() << "]";
     case SymbolTag:
       return OS << "[Symbol "
                 << (hv.getSymbol().isNotUniqued() ? "(External)" : "(Internal)")