Commitlog replayer: Range-check skip call

Fixes scylladb#15269

If segment being replayed is corrupted/truncated we can attempt skipping
completely bogues byte amounts, which can cause assert (i.e. crash) in
file_data_source_impl. This is not a crash-level error, so ensure we
range check the distance in the reader.

db/commitlog/commitlog.cc

@@ -2593,12 +2593,12 @@ db::commitlog::read_log_file(sstring filename, sstring pfx, commit_load_reader_f
             return eof || next == pos;
         }
         future<> skip(size_t bytes) {
-            pos += bytes;
-            if (pos > file_size) {
+            auto n = std::min(file_size - pos, bytes);
+            pos += n;
+            if (pos == file_size) {
                 eof = true;
-                pos = file_size;
             }
-            return fin.skip(bytes);
+            return fin.skip(n);
         }
         void stop() {
             eof = true;