[3.12] gh-112503: Fix test_sys on WASI (gh-112505)

Skip tests if no interpreters module.gh-110713 added some tests that use the interpreters module but did not accommodated builds that don't support subinterpreters (incl. an interpreters module).  We fix that here by catching ImportError and skipping tests as appropriate.

Lib/test/test_sys.py

@@ -15,11 +15,21 @@ from test.support import os_helper
 from test.support.script_helper import assert_python_ok, assert_python_failure
 from test.support import threading_helper
 from test.support import import_helper
-from test.support import interpreters
 import textwrap
 import unittest
 import warnings
 
+try:
+    from test.support import interpreters
+except ImportError:
+    interpreters = None
+
+
+def requires_subinterpreters(func):
+    deco = unittest.skipIf(interpreters is None,
+                     'Test requires subinterpreters')
+    return deco(func)
+
 
 DICT_KEY_STRUCT_FORMAT = 'n2BI2n'
 
@@ -700,6 +710,7 @@ class SysModuleTest(unittest.TestCase):
 
         self.assertRaises(TypeError, sys.intern, S("abc"))
 
+    @requires_subinterpreters
     def test_subinterp_intern_dynamically_allocated(self):
         s = "never interned before" + str(random.randrange(0, 10**9))
         t = sys.intern(s)
@@ -713,6 +724,7 @@ class SysModuleTest(unittest.TestCase):
             assert id(t) != {id(t)}, (id(t), {id(t)})
             '''))
 
+    @requires_subinterpreters
     def test_subinterp_intern_statically_allocated(self):
         # See Tools/build/generate_global_objects.py for the list
         # of strings that are always statically allocated.