[3.14] pythongh-141612: improve test_trampoline_works_with_forks coverage (pythonGH-141613) (python#141824)

pythongh-141612: improve `test_trampoline_works_with_forks` coverage (pythonGH-141613)
(cherry picked from commit f15f6d0)

Co-authored-by: Paresh Joshi <[email protected]>

Author: miss-islington

Lib/test/test_perf_profiler.py

@@ -160,6 +160,16 @@ def baz():
         self.assertIn(f"py::bar_fork:{script}", child_perf_file_contents)
         self.assertIn(f"py::baz_fork:{script}", child_perf_file_contents)
 
+        # The parent's map should not contain the child's symbols.
+        self.assertNotIn(f"py::foo_fork:{script}", perf_file_contents)
+        self.assertNotIn(f"py::bar_fork:{script}", perf_file_contents)
+        self.assertNotIn(f"py::baz_fork:{script}", perf_file_contents)
+
+        # The child's map should not contain the parent's symbols.
+        self.assertNotIn(f"py::foo:{script}", child_perf_file_contents)
+        self.assertNotIn(f"py::bar:{script}", child_perf_file_contents)
+        self.assertNotIn(f"py::baz:{script}", child_perf_file_contents)
+
     @unittest.skipIf(support.check_bolt_optimized(), "fails on BOLT instrumented binaries")
     def test_sys_api(self):
         code = """if 1: