dev-perl/Date-Manip: Ensure tests are run under TZ=UTC

dev-perl/Date-Manip: Ensure tests are run under TZ=UTC

On a stock gentoo install from stage 3, the TZ is set to "factory",
and unless this is changed, this causes these tests to fail.

As the point of tests are to ensure the code works, not to ensure
the users system is an arbitrary definition of sane, these tests
failing do more harm than good.

It may be worth adding additional check code to warn the user of this
condition, as its still there even for users who dont' run tests,
and a customized warning will give more gentoo-specific help than
some generic perl failure can.

Package-Manager: Portage-2.3.5, Repoman-2.3.2