[C++][Gandiva] date_time_test fails locally due to UTC and local time comparison #50399

Describe the bug, including details regarding any error messages, version, and platform.

While running release verification locally I ran into this test failure in Gandiva,

[ RUN      ] DateTimeTestProjector.TestDateTime
/var/folders/gf/3btcn6956190fx_xld0y_b9r0000gn/T/arrow-25.0.0.XXXXX.lfAWx3tMri/apache-arrow-25.0.0/cpp/src/gandiva/tests/date_time_test.cc:293: Failure
Value of: (exp_mm_from_date32)->Equals(outputs.at(3), arrow::EqualOptions().nans_equal(true))
  Actual: false
Expected: true
expected array: [
  1,
  12,
  6,
  7
] actual array: [
  1,
  12,
  7,
  7
]

There was a recent PR (#49953) that partially fixed issues in these test helpers related to time zone handling but I think it was incomplete. I also think we don't see this failure in CI because CI machines use UTC.

Component(s)

C++, Gandiva