Android: Add C/C++ debugging to SDK test app builds

Summary:
We've never been able to debug the Titanium SDK's C/C++ code via Android Studio before. We should enable this for easier C/C++ development. Currently, we're forced to debug our C/C++ code old-school style via logging functions.

Note:
This only applies to the Titanium SDK's test "app" project. It does not apply to customer apps built with Titanium since the SDK library we ship is a "release" version and does not provide debug symbols.

Implementation:
Google documents that they only support C/C++ debugging if you use CMake. This would mean we would have to replace our makefile usage with CMake files instead. While using CMake seems like a waste since Android is our only target, this is what Google pushes and they consider the ndk-build makefile system as a "legacy" feature.
https://developer.android.com/studio/projects/add-native-code.html#download-ndk