Remove references to stale benchmark data sources.

benchmarks/download_data.sh

@@ -1,5 +0,0 @@
-#! /bin/sh
-
-curl -O https://storage.googleapis.com/protobuf_opensource_benchmark_data/datasets.tar.gz
-tar -zvxf datasets.tar.gz
-

kokoro/linux/benchmark/run.sh

@@ -18,7 +18,6 @@ fi
 
 # download datasets for benchmark
 cd benchmarks
-./download_data.sh
 datasets=$(for file in $(find . -type f -name "dataset.*.pb" -not -path "./tmp/*"); do echo "$(pwd)/$file"; done | xargs)
 echo $datasets
 cd $oldpwd