Fix big-endian byte swap for WindowsResourceDumper.

[mnbvmar]

Summary

Previous patch incorrectly implemented swapping UTF16 byte order. Hope this should work alright, but I want to make sure beforehand.

[seurer]

I tried this patch on powerpc64 (BE) and it fixed the problem.

llvm/tools/llvm-readobj/WindowsResourceDumper.cpp

 
 std::string stripUTF16(const ArrayRef<UTF16> &UTF16Str) {
   std::string Result;
   Result.reserve(UTF16Str.size());
 
   for (UTF16 Ch : UTF16Str) {
     // UTF16Str will have swapped byte order in case of big-endian machines.
     // Swap it back in such a case.
-    support::ulittle16_t ChValue(Ch);
+    uint16_t ChValue = support::endian::byte_swap(Ch, support::little);
     if (ChValue <= 0xFF)
       Result += ChValue;
     else
       Result += '?';
   }
   return Result;
 }