Build tools version 37?

https://github.com/ReactiveCircus/android-emulator-runner/issues/448 all over again.

Refs:
 - https://github.com/ruffle-rs/ruffle-android/pull/760
 - https://github.com/ruffle-rs/ruffle-android/pull/759
 - https://github.com/ReactiveCircus/android-emulator-runner/pull/467

Thank you!