Include full minidump_stackwalk output in testcase

[choller]

Currently we have a lot of crashes on the server that only have partial symbols. It seems possible that there is something wrong with the symbolizing process, like missing symbols, corrupt dump or anything like that. In order to diagnose the problem, having the full minidump_stackwalk output in the testcase archive would be very helpful. This output should also include the stderr output, because that might have vital error messages.

[tysmith]

The following commits will allow you to enable the requested functionality via ec2spotmanager config UI. Add FFP_DEBUG_MDSW=1 to the list of EC2 Userdata Macros
MozillaSecurity/ffpuppet@fbb8ca2
https://github.com/MozillaSecurity/grizzly-config/commit/525d7d8096a44a98fac3245671f1921983873ee4