gh-105077: Fix test_tkinter refleak checking (GH-105078)

Use specific symbols from `` to avoid having `support`
overwritten by `test_tkinter`'s own `support` submodule.
diff --git a/Lib/test/test_tkinter/ b/Lib/test/test_tkinter/
index edcb449..b1181bc 100644
--- a/Lib/test/test_tkinter/
+++ b/Lib/test/test_tkinter/
@@ -1,18 +1,23 @@
 import os.path
 import unittest
-from test import support
-from import import_helper
+from import (
+    check_sanitizer,
+    import_helper,
+    load_package_tests,
+    requires,
+    )
-if support.check_sanitizer(address=True, memory=True):
+if check_sanitizer(address=True, memory=True):
     raise unittest.SkipTest("Tests involving libX11 can SEGFAULT on ASAN/MSAN builds")
 # Skip test if _tkinter wasn't built.
 # Skip test if tk cannot be initialized.
 def load_tests(*args):
-    return support.load_package_tests(os.path.dirname(__file__), *args)
+    return load_package_tests(os.path.dirname(__file__), *args)