GH#396: Update Objc-Test for Local & TravisCI

[erisu]

Platforms affected

ios tests

What does this PR do?

See #396 for more details.

• Upgrade Travis Environment to Xcode 9.3
  • Test Results: https://travis-ci.org/erisu/cordova-ios/builds/419492463
• Upgrade Objc-Tests Simulator Target Device to iPhone 8

This will allow tests to pass successfully on Travis CI and locally when using Xcode 9.3 or higher.

What testing has been done on this change?

• npm test locally
• TravisCI: https://travis-ci.org/erisu/cordova-ios/builds/419503187

[codecov-io]

Codecov Report

Merging #397 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #397   +/-   ##
=======================================
  Coverage   73.68%   73.68%           
=======================================
  Files          11       11           
  Lines        1463     1463           
=======================================
  Hits         1078     1078           
  Misses        385      385

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e0d3dad...0164d4c. Read the comment docs.

[dpogue]

👍 This makes sense to me