Merge "Add unit test for CarrierConfigLoader" am: 6ae1a17d5e am: 5eae924e63 am: d846a8ead9

Original change: https://android-review.googlesource.com/c/platform/packages/services/Telephony/+/1652975

Change-Id: I444a1fc6b5ee9e20fda5e7411292c7d646c658ae