Improve Android NDK symbolication documentation - CMake support

[mmarczell-graphisoft]

The documentation says this:

Option 1: Upload native binaries

Put all .so files from the project's obj/local/$ABI/ directory into a .zip file.

There is no such directory in my build tree. The documentation does not mention that this directory is specific to ndk-build. My app is built with CMake. CMake based Release builds strip the debug symbols from the .so files. I don't know where the unstripped .so files are located in a CMake based build, or even whether they at all exist after the build has finished.

The documentation should indicate that this instruction is for ndk-build based builds, as well as provide equivalent instructions for CMake based builds.

[mmarczell-graphisoft]

According to https://developer.android.com/build/shrink-code#native-crash-support, the unstripped .so files' location in a CMake based build is dependent on the version of the Android Gradle plugin.

Android Gradle plugin version 4.0 or earlier

app/build/intermediates/cmake/universal/release/obj/

Android Gradle plugin version 4.1 or later

Undocumented, variable path. In my particular case it was app/build/intermediates/cxx/RelWithDebInfo/e2gf2c5g/obj/arm64-v8a/

[mmarczell-graphisoft]

Even after uploading all of my .so files in a zip, my Android native crashes are not getting symbolicated.