Revert "Temporarily remove TimeZoneDetectorStatsTest"

This reverts commit 2e763a69f91f24e1d694d22b47e19be591a7a313.

Reason for revert: Re-institute tests after fixes
Bug: 228457046
Test: Treehugger

Change-Id: I0dd8076e07c9cf80b5f7f01c2289cf448a4240d5
2 files changed