[Swift 3.0] Fix crash for looking up sim id on real device

[kdawgwilk]

This fixes a crash when trying to lookup a simulator identifier on a real device. Fixes Issue #60

[kdawgwilk]

Alright this is ready to go. I found a better API to get the ENV var for the simulator that won't crash if it doesn't exist. and I give a default "Unknown" value as the identifier because I tried the identifier passed in but it caused and infinite recursion :(

[dennisweissmann]

Hi @kdagwilk! Thank you so much for exploring and solving this! This is so much nicer (and obviously better) 💯. One small thing: this code doesn't compile (during the transition to Swift 3 we lowercased the enum cases, so it should be simulator (with a small "s"). If you could fix that and then CI hopefully passes, I will merge it :) thanks so much 🙏 This is awesome 👏 🎉

[dennisweissmann]

My comment from #61 applies here too, I think :( sorry for the trouble!

[kdawgwilk]

It looks like it failed on a few sims but is succeeding everywhere else :( Anything I need to do on my end or is it just CI being flakey?

[dennisweissmann]

😔 sigh ... it's been ultra flaky for a few months now, LGTM, thanks! 🙏