[ELF] NFC: Remove unnecessary function call

[jhenderson]

Summary

StringTableSection does not implement postThunkContents, so calling it on these sections is pointless (it calls an empty virtual function), and we can remove it.

[ruiu]

LGTM

ELF/Writer.cpp

template <class ELFT> void Writer<ELFT>::finalizeSections() {
 
   // Fill other section headers. The dynamic table is finalized
   // at the end because some tags like RELSZ depend on result
   // of finalizing other sections.
   for (OutputSection *Sec : OutputSections)
     Sec->finalize<ELFT>();
 
   // createThunks may have added local symbols to the static symbol table
-  applySynthetic({InX::SymTab, InX::ShStrTab, InX::StrTab},
+  applySynthetic({InX::SymTab},
                  [](SyntheticSection *SS) { SS->postThunkContents(); });
 }
 
 template <class ELFT> void Writer<ELFT>::addPredefinedSections() {
   // ARM ABI requires .ARM.exidx to be terminated by some piece of data.
   // We have the terminater synthetic section class. Add that at the end.
   OutputSection *Cmd = findSection(".ARM.exidx");
   if (!Cmd || !Cmd->Live || Config->Relocatable)