Disable shell benchmarks (flutter#17038)

See flutter#52263

TBR: @chinmaygarde

Author: liyuqian

.cirrus.yml

@@ -60,12 +60,10 @@ task:
         cd $ENGINE_PATH/src/out/host_release/
         ./txt_benchmarks --benchmark_format=json > txt_benchmarks.json
         ./fml_benchmarks --benchmark_format=json > fml_benchmarks.json
-        ./shell_benchmarks --benchmark_format=json > shell_benchmarks.json
         cd $ENGINE_PATH/src/flutter/testing/benchmark
         pub get
         dart bin/parse_and_send.dart ../../../out/host_release/txt_benchmarks.json
         dart bin/parse_and_send.dart ../../../out/host_release/fml_benchmarks.json
-        dart bin/parse_and_send.dart ../../../out/host_release/shell_benchmarks.json
     - name: build_and_test_linux_unopt_debug
       compile_host_script: |
         cd $ENGINE_PATH/src