gh-124008: Fix calculation of the number of written bytes for the Windows console (GH-124059)

Since MultiByteToWideChar()/WideCharToMultiByte() is not reversible if
the data contains invalid UTF-8 sequences, use binary search to
calculate the number of written bytes from the number of written
characters.

Also fix writing incomplete UTF-8 sequences.

Also fix handling of memory allocation failures.

Lib/test/test_winconsoleio.py

@@ -142,6 +142,29 @@ class WindowsConsoleIOTests(unittest.TestCase):
         with ConIO('CONOUT$', 'w') as f:
             self.assertEqual(f.write(b''), 0)
 
+    @requires_resource('console')
+    def test_write(self):
+        testcases = []
+        with ConIO('CONOUT$', 'w') as f:
+            for a in [
+                b'',
+                b'abc',
+                b'\xc2\xa7\xe2\x98\x83\xf0\x9f\x90\x8d',
+                b'\xff'*10,
+            ]:
+                for b in b'\xc2\xa7', b'\xe2\x98\x83', b'\xf0\x9f\x90\x8d':
+                    testcases.append(a + b)
+                    for i in range(1, len(b)):
+                        data = a + b[:i]
+                        testcases.append(data + b'z')
+                        testcases.append(data + b'\xff')
+                        # incomplete multibyte sequence
+                        with self.subTest(data=data):
+                            self.assertEqual(f.write(data), len(a))
+            for data in testcases:
+                with self.subTest(data=data):
+                    self.assertEqual(f.write(data), len(data))
+
     def assertStdinRoundTrip(self, text):
         stdin = open('CONIN$', 'r')
         old_stdin = sys.stdin