Avoid use of TimeZoneDistro.equals() method

The TimeZoneDistro method is going away.

make -j30 FrameworksServicesTests
adb install -r -g \
    "out/target/product/angler/data/app/FrameworksServicesTests/FrameworksServicesTests.apk"
adb shell am instrument -e package com.android.server.timezone -w \
    com.android.frameworks.servicestests \
    "com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner"

Test: See above
Test: Manual
Bug: 31008728

Change-Id: Id90cf7ce534b888bf6df1bf1dc9d497608dcdbe9