[Fix](compile) Fix gcc compile on master (#33864)

This is imported by #33511. wrongly used

ColumnStr<T> ();

which violate C++20 standard(see https://wg21.cmeerw.net/cwg/issue2237) but still supported by clang up until now(see llvm/llvm-project#58112)

be/src/vec/columns/column_string.cpp

@@ -296,6 +296,7 @@ ColumnPtr ColumnStr<T>::permute(const IColumn::Permutation& perm, size_t limit)
 
     if (perm.size() < limit) {
         LOG(FATAL) << "Size of permutation is less than required.";
+        __builtin_unreachable();
     }
 
     if (limit == 0) {