Added sparkspot model.
Summary: Lite interpereter does not have softplus and sub ops for this model.
Test Plan:
buck run fbsource//xplat/aibench:run_bench -- -b ../xplat/aibench/specifications/models/pytorch/mobile_migration/sparkspot.json --platform android --framework pytorch --remote --devices SM-G960U-8.0.0-26
https://our.intern.facebook.com/intern/aibench/details/890521439770638
buck run fbsource//xplat/aibench:run_bench -- -b ../xplat/aibench/specifications/models/pytorch/mobile_migration/sparkspot.json --platform android/arm64 --framework pytorch --remote --devices SM-G960U-8.0.0-26
https://our.intern.facebook.com/intern/aibench/details/485779747361527
For Caffe2:
buck run fbsource//xplat/aibench:run_bench -- -b ../xplat/aibench/specifications/models/caffe2/mobile_migration/sparkspot.json --platform android --framework caffe2 --remote --devices SM-G950U-7.0-24
https://our.intern.facebook.com/intern/aibench/details/177482569133423
Reviewed By: ljk53, iseeyuan
Differential Revision: D19757721
fbshipit-source-id: cdd4b39d072925fc8de17184f2c90918de6245ba
