[3.14] gh-144639: Ruff: target Python 3.14 syntax in Lib/test (GH-144656)

(cherry picked from commit 81484c5)

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: 3 people

Lib/test/.ruff.toml

@@ -1,6 +1,7 @@
 extend = "../../.ruff.toml"  # Inherit the project-wide settings
 
-target-version = "py312"
+# Unlike Tools/, tests can use newer syntax than PYTHON_FOR_REGEN
+target-version = "py314"
 
 extend-exclude = [
     # Excluded (run with the other AC files in its own separate ruff job in pre-commit)
@@ -15,15 +16,6 @@ extend-exclude = [
     "test_grammar.py",
 ]
 
-[per-file-target-version]
-# Type parameter defaults
-"test_type_params.py" = "py313"
-
-# Template string literals
-"test_annotationlib.py" = "py314"
-"test_string/test_templatelib.py" = "py314"
-"test_tstring.py" = "py314"
-
 [lint]
 select = [
     "F811",  # Redefinition of unused variable (useful for finding test methods with the same name)