[FR] add hints to ndk-stack

ndk-stack could probably perform some basic analysis of the stack trace and provide some hints to the user.

Specifically, it would be very helpful for diagnosing misuse of https://github.com/android/ndk/issues/837, since the stack trace for getting that wrong will look quite confusing to anyone that doesn't know to expect it.

Start at the ndk-stack entry point and compare its current stack-trace handling with the misuse described in issue 837. Done means defining and implementing useful diagnostic hints for that confusing trace, with behavior and scope established before coding.

Written by the indexing model from the issue text.