Revert "Disable testing on S20 that is offline" (#5833)

The phone is back online.

I didn't revert the move of the line to skip the S10 test. That phone is still offline and I think
having the skip statement at the top of a step makes it more obvious.

Reverts google/iree#5828
diff --git a/build_tools/buildkite/cmake/android/arm64-v8a/benchmark.yml b/build_tools/buildkite/cmake/android/arm64-v8a/benchmark.yml
index c7e2caf..6801337 100644
--- a/build_tools/buildkite/cmake/android/arm64-v8a/benchmark.yml
+++ b/build_tools/buildkite/cmake/android/arm64-v8a/benchmark.yml
@@ -54,7 +54,6 @@
     timeout_in_minutes: "15"
 
   - label: "benchmark on Galaxy S20 (exynos-990, mali-g77)"
-    skip: "Currently offline"
     commands:
       - "buildkite-agent artifact download --step build model-S20-artifacts.tgz ./"
       - "buildkite-agent artifact download --step build flagfiles.tgz ./"
diff --git a/build_tools/buildkite/cmake/android/arm64-v8a/pipeline.yml b/build_tools/buildkite/cmake/android/arm64-v8a/pipeline.yml
index 4df5010..b2b2fd3 100644
--- a/build_tools/buildkite/cmake/android/arm64-v8a/pipeline.yml
+++ b/build_tools/buildkite/cmake/android/arm64-v8a/pipeline.yml
@@ -26,7 +26,6 @@
   - wait
 
   - label: "test on Galaxy S20 (exynos-990, mali-g77)"
-    skip: "Currently offline"
     commands:
       - "buildkite-agent artifact download --step build build-artifacts.tgz ./"
       - "tar xzf build-artifacts.tgz"