bpo-45205: Make test_compileall quiet (GH-28356) (GH-28370)

Make test_compileall quiet: test_year_2038_mtime_compilation() and
test_larger_than_32_bit_times() of test_compileall no longer log
"Compiling ..." messages to stdout.
(cherry picked from commit cc057ff)

Co-authored-by: Victor Stinner <vstinner@python.org>

Lib/test/test_compileall.py

@@ -91,7 +91,8 @@ def test_year_2038_mtime_compilation(self):
             os.utime(self.source_path, (2**32 - 1, 2**32 - 1))
         except (OverflowError, OSError):
             self.skipTest("filesystem doesn't support timestamps near 2**32")
-        self.assertTrue(compileall.compile_file(self.source_path))
+        with contextlib.redirect_stdout(io.StringIO()):
+            self.assertTrue(compileall.compile_file(self.source_path))
 
     def test_larger_than_32_bit_times(self):
         # This is similar to the test above but we skip it if the OS doesn't
@@ -100,7 +101,8 @@ def test_larger_than_32_bit_times(self):
             os.utime(self.source_path, (2**35, 2**35))
         except (OverflowError, OSError):
             self.skipTest("filesystem doesn't support large timestamps")
-        self.assertTrue(compileall.compile_file(self.source_path))
+        with contextlib.redirect_stdout(io.StringIO()):
+            self.assertTrue(compileall.compile_file(self.source_path))
 
     def recreation_check(self, metadata):
         """Check that compileall recreates bytecode when the new metadata is