feat: remove GraalPy 3.11 (gp311) support (#2895)

Drops the GraalPy 3.11 / GraalPy 24.2 builds (gp311_242) as agreed in
pypa/cibuildwheel#2741: a ~6-month overlap after the GraalPy 25 (gp312)
release. GraalPy 3.12 (gp312_250) stays.

This also removes the GraalPy 24-only workarounds that were explicitly
marked "Remove when GraalPy 24.x is dropped":
- the Visual Studio compiler-discovery (vswhere) and build-isolation
  (graalpython#491) workarounds in the Windows backend
- the issue-491 Windows skip/filter hacks in test_pep518 and
  test_dependency_versions (added in the original GraalPy PR #1538 and
  unneeded since GraalPy 25 per #2597)

The uv-doesn't-support-graalpy skip (#2754), the `graalpy` enable group,
and the generated constraints pins apply to all GraalPy and are kept.

Assisted-by: ClaudeCode:claude-opus-4.8

test/test_dependency_versions.py

@@ -179,19 +179,6 @@ def test_dependency_constraints(
         msg = f"Unknown method: {method}"
         raise ValueError(msg)
 
-    skip = ""
-
-    if (
-        utils.get_platform() == "windows"
-        and method == "file"
-        and build_frontend_env_nouv["CIBW_BUILD_FRONTEND"] == "build"
-    ):
-        # GraalPy 24 fails to discover its standard library when a venv is created
-        # from a virtualenv seeded executable. See
-        # https://github.com/oracle/graalpython/issues/491 and remove this once
-        # GraalPy 24 is dropped
-        skip = "gp311*"
-
     # cross-platform Python script for dependency constraint checks
     before_build_script = project_dir / "check_versions.py"
     before_build_script.write_text(CHECK_VERSIONS_SCRIPT)
@@ -200,7 +187,6 @@ def test_dependency_constraints(
     actual_wheels = utils.cibuildwheel_run(
         project_dir,
         add_env={
-            "CIBW_SKIP": skip,
             "CIBW_DEPENDENCY_VERSIONS": dependency_version_option,
             "CIBW_BEFORE_BUILD": f"python {before_build_script.name}",
             "EXPECTED_VERSIONS": json.dumps(tool_versions),
@@ -212,9 +198,4 @@ def test_dependency_constraints(
     # also check that we got the right wheels
     expected_wheels = utils.expected_wheels("spam", "0.1.0", single_python=True)
 
-    if skip == "gp*":
-        # See reference to https://github.com/oracle/graalpython/issues/491
-        # above
-        expected_wheels = [w for w in expected_wheels if "graalpy311" not in w]
-
     assert set(actual_wheels) == set(expected_wheels)