Remove assertion in PyThreadState_Clear().

Author: ZeroIntensity

Python/pystate.c

@@ -1625,7 +1625,11 @@ PyThreadState_Clear(PyThreadState *tstate)
 {
     assert(tstate->_status.initialized && !tstate->_status.cleared);
     assert(current_fast_get()->interp == tstate->interp);
-    assert(!_PyThreadState_IsRunningMain(tstate));
+    // GH-126016: In the _interpreters module, KeyboardInterrupt exceptions
+    // during PyEval_EvalCode() are sent to finalization, which doesn't let us
+    // mark threads as "not running main". So, for now this assertion is
+    // disabled.
+    // XXX assert(!_PyThreadState_IsRunningMain(tstate));
     // XXX assert(!tstate->_status.bound || tstate->_status.unbound);
     tstate->_status.finalizing = 1;  // just in case