Revert "Move ReachableCode exception to test.support"

This reverts commit 56a50ca.

Lib/test/support/__init__.py

@@ -23,7 +23,7 @@
     # globals
     "PIPE_MAX_SIZE", "verbose", "max_memuse", "use_resources", "failfast",
     # exceptions
-    "ReachableCode", "Error", "TestFailed", "TestDidNotRun", "ResourceDenied",
+    "Error", "TestFailed", "TestDidNotRun", "ResourceDenied",
     # io
     "record_original_stdout", "get_original_stdout", "captured_stdout",
     "captured_stdin", "captured_stderr", "captured_output",
@@ -107,11 +107,6 @@
 STDLIB_DIR = os.path.dirname(TEST_HOME_DIR)
 REPO_ROOT = os.path.dirname(STDLIB_DIR)
 
-class ReachableCode(Exception):
-    """Exception to raise to indicate that some code was reached.
-
-    Use this exception if using mocks is not a good alternative.
-    """
 
 class Error(Exception):
     """Base class for regression test exceptions."""

Lib/test/test_asyncio/test_futures.py

@@ -14,7 +14,6 @@
 import warnings
 from test.test_asyncio import utils as test_utils
 from test import support
-from test.support import ReachableCode
 
 
 def tearDownModule():
@@ -33,6 +32,13 @@ def last_cb():
     pass
 
 
+class ReachableCode(Exception):
+    """Exception to raise to indicate that some code was reached.
+
+    Use this exception if using mocks is not a good alternative.
+    """
+
+
 class SimpleEvilEventLoop(asyncio.base_events.BaseEventLoop):
     """Base class for UAF and other evil stuff requiring an evil event loop."""