gh-115142: Skip some test cases in ``Lib/test/test_compile`` if ``_testinternalcapi`` is not available (#124474)

* Skip some test cases if "_testinternalcapi" is not available and if the test suite is
   running on another implementation than CPython.

Lib/test/test_compile.py

@@ -13,7 +13,10 @@ import tempfile
 import types
 import textwrap
 import warnings
-import _testinternalcapi
+try:
+    import _testinternalcapi
+except ImportError:
+    _testinternalcapi = None
 
 from test import support
 from test.support import (script_helper, requires_debug_ranges, run_code,
@@ -2645,6 +2648,8 @@ class TestStackSizeStability(unittest.TestCase):
             """
         self.check_stack_size(snippet, async_=True)
 
+@support.cpython_only
+@unittest.skipIf(_testinternalcapi is None, 'need _testinternalcapi module')
 class TestInstructionSequence(unittest.TestCase):
     def compare_instructions(self, seq, expected):
         self.assertEqual([(opcode.opname[i[0]],) + i[1:] for i in seq.get_instructions()],