[llvm-objcopy][MachO] Fix strict-aliasing warning. NFCI

[seiya]

Summary

Use MachOObjectFile::isRelocationScattered instead of reinterpret_cast.

Fixes https://bugs.llvm.org/show_bug.cgi?id=42360

[alexander-shaposhnikov]

LG

llvm/trunk/tools/llvm-objcopy/MachO/MachOReader.cpp

for (; reinterpret_cast<const void *>(Curr) < End; Curr++) {
 
     S.Relocations.reserve(S.NReloc);
     for (auto RI = MachOObj.section_rel_begin(SecRef->getRawDataRefImpl()),
               RE = MachOObj.section_rel_end(SecRef->getRawDataRefImpl());
          RI != RE; ++RI) {
       RelocationInfo R;
       R.Symbol = nullptr; // We'll fill this field later.
       R.Info = MachOObj.getRelocation(RI->getRawDataRefImpl());
-      R.Scattered =
-          reinterpret_cast<MachO::scattered_relocation_info *>(&R.Info)
-              ->r_scattered;
+      R.Scattered = MachOObj.isRelocationScattered(R.Info);
       S.Relocations.push_back(R);
     }
 
     assert(S.NReloc == S.Relocations.size() &&
            "Incorrect number of relocations");
   }
   return Sections;
 }