[llvm] [llvm-objdump][ELF]Fix crash when reading strings from .dynstr (PR #125679)

[Ruoyu Qiu via llvm-commits]

================
@@ -63,14 +63,22 @@ static Expected<StringRef> getDynamicStrTab(const ELFFile<ELFT> &Elf) {
   if (!DynamicEntriesOrError)
     return DynamicEntriesOrError.takeError();
 
+  typename ELFT::Xword StringTableSize{0};
----------------
cabbaken wrote:

> `typename ELFT::Xword StringTableSize = 0;`

I got error with this code.
```
No viable conversion from 'int' to 'typename ELFType<llvm::endianness::little, false>::Xword' (aka 'packed_endian_specific_integral<unsigned long, (llvm::endianness)1, 1>')
```

https://github.com/llvm/llvm-project/pull/125679