We reuse code from Skia to walk the stack on Posix platforms. See:
https://github.com/google/skia/blob/master/tools/CrashHandler.cpp

On Windows we use a BSD-licensed tool called StackWalker. See:
https://github.com/JochenKalmbach/StackWalker

This allows us to get high quality stack traces on Win/Linux/Mac.

Bug: angleproject:3162
Change-Id: I9c50ede2c6a41ed0ee85a0507372df42a487bcef
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1632950
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>