Make double uninstall test independent of order

Discovery order depends on the metadata backend.

For the importlib backend, it has changed following the previous commit,
because now the .egg-link file is found while inspecting site-package,
and the .egg directory is found after because it comes after in sys.path.

Before the dedictated .egg detection logic was triggered while inspecting
site package and found it, before looking for .egg-link.

Author: sbidoul

tests/functional/test_uninstall.py

@@ -628,10 +628,6 @@ def test_uninstall_with_symlink(
     assert symlink_target.stat().st_mode == st_mode
 
 
-@pytest.mark.skipif(
-    "sys.version_info >= (3, 14)",
-    reason="Uninstall of .egg distributions not supported in Python 3.14+",
-)
 def test_uninstall_setuptools_develop_install(
     script: PipTestEnvironment, data: TestData
 ) -> None:
@@ -642,11 +638,19 @@ def test_uninstall_setuptools_develop_install(
     script.assert_installed(FSPkg="0.1.dev0")
     # Uninstall both develop and install
     uninstall = script.pip("uninstall", "FSPkg", "-y")
-    assert any(p.suffix == ".egg" for p in uninstall.files_deleted), str(uninstall)
     uninstall2 = script.pip("uninstall", "FSPkg", "-y")
-    assert (
+    # Depending on the metadata backend, the egg-link will be uninstalled first
+    # or second, so we use xor in the assertions below.
+    assert (join(script.site_packages, "FSPkg.egg-link") in uninstall.files_deleted) ^ (
         join(script.site_packages, "FSPkg.egg-link") in uninstall2.files_deleted
-    ), str(uninstall2)
+    )
+    assert any(
+        p.name.startswith("FSPkg") and p.suffix == ".egg"
+        for p in uninstall.files_deleted
+    ) ^ any(
+        p.name.startswith("FSPkg") and p.suffix == ".egg"
+        for p in uninstall2.files_deleted
+    )
     script.assert_not_installed("FSPkg")