Remove test for America/Hermosillo transition at the epoch

A recent update [0] to the IANA timezone database has improved the
historical accuracy of transitions in Mexico. It turns out that the
transition at the start of 1970 was not a real event. The only actual
change then was that Mazatlan has followed the main Mexico zone rules
since then, having ignored some transitions of the main zone in
earlier decades.

[0] eggert/tz@812aff3

Picking to 6.8 got a trivially-resolved conflict due to dev having one
more BackendKludges flag to take into account. Removed 6.5 from the
destinations for picking because the removed test was added since
then.

Fixes: QTQAINFRA-6757
Change-Id: I65d8ea1dfa76ce635bf11ffcc1ded8c9ceaf9fec
Reviewed-by: Paul Wicking <[email protected]>
(cherry picked from commit 8a27c31)
(cherry picked from commit d5bb570)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>

tests/auto/corelib/time/qdate/tst_qdate.cpp

@@ -554,9 +554,6 @@ void tst_QDate::startOfDay_endOfDay_data()
         const QTime end;
         const BackendKludges msOpt;
     } transitions[] = {
-        // The western Mexico time-zones skipped the first hour of 1970.
-        { "BajaMexico", "America/Hermosillo", QDate(1970, 1, 1), QTime(1, 0), late, MsNoStart },
-
         // Compare tst_QDateTime::fromStringDateFormat(ISO 24:00 in DST).
         { "Brazil", "America/Sao_Paulo", QDate(2008, 10, 19), QTime(1, 0), late, Clean },