Move frozen-dataclass PEP 695 variance test to check-python313.test

The test exercises __replace__ synthesis, which the dataclass plugin only
generates on Python 3.13+.  check-python313.test defaults to python_version
(3, 13) via testfile_pyversion; the explicit # flags: --python-version 3.13
pragma is therefore redundant and has been dropped, consistent with all
other tests in that file.

Assistant-Model: Claude Code

Author: allanlewis

test-data/unit/check-python312.test

@@ -248,23 +248,6 @@ inv2: Invariant[int] = Invariant[float]([1])  # E: Incompatible types in assignm
 [builtins fixtures/tuple.pyi]
 [typing fixtures/typing-full.pyi]
 
-[case testPEP695InferVarianceInFrozenDataclassPython313]
-# flags: --python-version 3.13
-# On Python 3.13+ the dataclass plugin synthesizes a __replace__ method whose
-# keyword parameters reuse the field types. Being plugin-generated, it must not
-# drag the type variable into a contravariant position and make an otherwise
-# covariant frozen dataclass invariant.
-from dataclasses import dataclass
-
-@dataclass(frozen=True)
-class Covariant[T]:
-    x: T
-
-cov1: Covariant[float] = Covariant[int](1)
-cov2: Covariant[int] = Covariant[float](1)  # E: Incompatible types in assignment (expression has type "Covariant[float]", variable has type "Covariant[int]")
-[builtins fixtures/tuple.pyi]
-[typing fixtures/typing-full.pyi]
-
 [case testPEP695InferVarianceWithAttrsFrozen]
 import attrs
 

test-data/unit/check-python313.test

@@ -480,3 +480,19 @@ reveal_type(x)  # N: Revealed type is "builtins.list[tuple[()]]"
 reveal_type(y)  # N: Revealed type is "builtins.list[tuple[()]]"
 reveal_type(z)  # N: Revealed type is "builtins.list[tuple[()]]"
 [builtins fixtures/tuple.pyi]
+
+[case testPEP695InferVarianceInFrozenDataclass]
+# On Python 3.13+ the dataclass plugin synthesizes a __replace__ method whose
+# keyword parameters reuse the field types. Being plugin-generated, it must not
+# drag the type variable into a contravariant position and make an otherwise
+# covariant frozen dataclass invariant.
+from dataclasses import dataclass
+
+@dataclass(frozen=True)
+class Covariant[T]:
+    x: T
+
+cov1: Covariant[float] = Covariant[int](1)
+cov2: Covariant[int] = Covariant[float](1)  # E: Incompatible types in assignment (expression has type "Covariant[float]", variable has type "Covariant[int]")
+[builtins fixtures/tuple.pyi]
+[typing fixtures/typing-full.pyi]