Fix tz rules (dotnet/coreclr#10169)

Fix tz rules (dotnet/coreclr#10169)

* Fix the TZ Rule data on Linux

On Linux when the caller ask for the TZ adjustment rules we convert the internal stored rule data from UTC to local time. we used to TZI.Convert which is wrong because calculating the start the daylight start time should always not include the daylight delta because we didn't start the daylight saving yet. and calculating the end of daylight should always include the daylight delta because we were in the daylight saving period.

The fix here is manually calculating the start and end of the daylight saving inside the rule

* Revert the comment change

* Add a comment

Commit migrated from https://github.com/dotnet/coreclr/commit/c2b5d5a707e3bb037df847e17b4e55e19fd5bfa8