DEPR: check_datetimelike_compat in tm.assert_foo functions

[jbrockmendel]

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Reproducible Example

NA

Issue Description

We only use this in pandas.tests.io.test_stata, and implementing #55564 will remove those usages. It also doesn't consider as equal dt64[us]-vs-dt64[ns], only object-vs-dt64[ns] AFAICT, which makes it less useful.

Expected Behavior

NA

Installed Versions

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