Test suite type hint metadata fixturization x 5.

This commit is the next in a commit chain fundamentally refactoring our
test suite to leverage space- and time-efficient `pytest` session-scoped
fixtures rather than space- and time-inefficient ad-hoc machinery
previously defined by the `beartype_test.a00_unit.data.hint.pep`
subpackage, which @leycec requires to preserve personal sanity while
maintaining this lumbering juggernaut but nobody else particularly cares
about. It's best *not* to ask what this is about. Just know that our
test suite is demonstrably improving into something maintainable that
will no longer destroy @leycec's precious sanity points.
(*Opportunistic tuning of an important importuning!*)

beartype_test/a00_unit/data/hint/pep/data_pep.py

@@ -160,6 +160,8 @@ def _init() -> None:
     '''
 
     # Defer fixture-specific imports.
+    from beartype_test.a00_unit.data.hint.pep.proposal._data_pep544 import (
+        hints_pep_meta_pep544)
     from beartype_test.a00_unit.data.hint.pep.proposal._data_pep586 import (
         hints_pep_meta_pep586)
     from beartype_test.a00_unit.data.hint.pep.proposal._data_pep589 import (
@@ -180,6 +182,7 @@ def _init() -> None:
 
     # Tuple of all fixtures defining "HINTS_PEP_META" subiterables.
     HINTS_PEP_META_FIXTURES = (
+        hints_pep_meta_pep544,
         hints_pep_meta_pep586,
         hints_pep_meta_pep589,
         hints_pep_meta_pep593,