[llvm-objcopy][MachO] Fix method names. NFC.

[alexander-shaposhnikov]

@seiya i think this diff is safe to commit (if it has not been committed yet)

[seiya]

In D65540#1632664, @alexshap wrote:

@seiya i think this diff is safe to commit (if it has not been committed yet)

Thank you for the ping! I'll commit this patch along with other accepted patches by Monday. (I use arc patch to apply patches but it seems that arc requires applying the parent patches (D63395/D65539) before.)

[seiya]

Rebase for the sake of arc patch.

[seiya]

Rebase for the sake of arc patch.

llvm/tools/llvm-objcopy/MachO/MachOWriter.cpp

void writeNListEntry(const SymbolEntry &SE, bool IsLittleEndian, char *&Out,
   ListEntry.n_value = SE.n_value;
 
   if (IsLittleEndian != sys::IsLittleEndianHost)
     MachO::swapStruct(ListEntry);
   memcpy(Out, reinterpret_cast<const char *>(&ListEntry), sizeof(NListType));
   Out += sizeof(NListType);
 }
 
-void MachOWriter::writeSymbolTable() {
+void MachOWriter::writeStringTable() {
   if (!O.SymTabCommandIndex)
     return;
   const MachO::symtab_command &SymTabCommand =
       O.LoadCommands[*O.SymTabCommandIndex]
           .MachOLoadCommand.symtab_command_data;
 
   uint8_t *StrTable = (uint8_t *)B.getBufferStart() + SymTabCommand.stroff;
   LayoutBuilder.getStringTableBuilder().write(StrTable);
 }
 
-void MachOWriter::writeStringTable() {
+void MachOWriter::writeSymbolTable() {
   if (!O.SymTabCommandIndex)
     return;
   const MachO::symtab_command &SymTabCommand =
       O.LoadCommands[*O.SymTabCommandIndex]
           .MachOLoadCommand.symtab_command_data;
 
   char *SymTable = (char *)B.getBufferStart() + SymTabCommand.symoff;
   for (auto Iter = O.SymTable.Symbols.begin(), End = O.SymTable.Symbols.end();