[3.14] gh-134557: Suppress immortalization in _PyCode_GetScriptXIData under free-threading (gh134738)

Disable immortalization around Py_CompileString*().

The same approach as 332356b that fixed the refleaks in compile() and eval().

E: 09e72cf can pass test_capi, test_sys and test__interpchannels with this patch for me.

(cherry picked from commit c60f39a, AKA gh-134686)

Co-authored-by: neonene <53406459+neonene@users.noreply.github.com>

Author: miss-islington

Python/crossinterp.c

@@ -908,8 +908,15 @@ get_script_xidata(PyThreadState *tstate, PyObject *obj, int pure,
             }
             goto error;
         }
+#ifdef Py_GIL_DISABLED
+        // Don't immortalize code constants to avoid memory leaks.
+        ((_PyThreadStateImpl *)tstate)->suppress_co_const_immortalization++;
+#endif
         code = Py_CompileStringExFlags(
                     script, filename, Py_file_input, &cf, optimize);
+#ifdef Py_GIL_DISABLED
+        ((_PyThreadStateImpl *)tstate)->suppress_co_const_immortalization--;
+#endif
         Py_XDECREF(ref);
         if (code == NULL) {
             goto error;