Fix NNAPI mlts test script to read output from /storage/emulated/0 instead am: f45ee41ec1 am: cfaaa90a22

Original change: https://android-review.googlesource.com/c/platform/test/mlts/benchmark/+/2418599

Change-Id: I4e9af4c4bd3fcff187a977253a1dffd751f5deea
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>