ParagraphStyle uses the wrong bit mask (flutter#43070)

For example, `_encodeParagraphStyle` says:

```dart
  if (locale != null) {
    result[0] |= 1 << 12;
    // Passed separately to native.
  }
```

We know `1<<12` is 4096.

On the other hand, the old code uses `0x800`, which is 2048.

And the strutStyle field is missing.

*Replace this paragraph with a description of what this PR is changing or adding, and why. Consider including before/after screenshots.*

*List which issues are fixed by this PR. You must list at least one issue.*

*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

lib/ui/text.dart

@@ -1829,8 +1829,9 @@ class ParagraphStyle {
              'fontFamily: ${    _encoded[0] & 0x080 == 0x080 ? _fontFamily                       : "unspecified"}, '
              'fontSize: ${      _encoded[0] & 0x100 == 0x100 ? _fontSize                         : "unspecified"}, '
              'height: ${        _encoded[0] & 0x200 == 0x200 ? "${_height}x"                     : "unspecified"}, '
-             'ellipsis: ${      _encoded[0] & 0x400 == 0x400 ? '"$_ellipsis"'                    : "unspecified"}, '
-             'locale: ${        _encoded[0] & 0x800 == 0x800 ? _locale                           : "unspecified"}'
+             'strutStyle: ${    _encoded[0] & 0x400 == 0x400 ? _strutStyle                       : "unspecified"}, '
+             'ellipsis: ${      _encoded[0] & 0x800 == 0x800 ? '"$_ellipsis"'                    : "unspecified"}, '
+             'locale: ${        _encoded[0] & 0x1000 == 0x1000 ? _locale                         : "unspecified"}'
            ')';
   }
 }

testing/dart/text_test.dart

@@ -56,10 +56,10 @@ void testParagraphStyle() {
   final ParagraphStyle ps3 = ParagraphStyle(fontWeight: FontWeight.w700, fontSize: 12.0, height: 123.0);
 
   test('ParagraphStyle toString works', () {
-    expect(ps0.toString(), equals('ParagraphStyle(textAlign: unspecified, textDirection: TextDirection.ltr, fontWeight: unspecified, fontStyle: unspecified, maxLines: unspecified, textHeightBehavior: unspecified, fontFamily: unspecified, fontSize: 14.0, height: unspecified, ellipsis: unspecified, locale: unspecified)'));
-    expect(ps1.toString(), equals('ParagraphStyle(textAlign: unspecified, textDirection: TextDirection.rtl, fontWeight: unspecified, fontStyle: unspecified, maxLines: unspecified, textHeightBehavior: unspecified, fontFamily: unspecified, fontSize: 14.0, height: unspecified, ellipsis: unspecified, locale: unspecified)'));
-    expect(ps2.toString(), equals('ParagraphStyle(textAlign: TextAlign.center, textDirection: unspecified, fontWeight: FontWeight.w800, fontStyle: unspecified, maxLines: unspecified, textHeightBehavior: unspecified, fontFamily: unspecified, fontSize: 10.0, height: 100.0x, ellipsis: unspecified, locale: unspecified)'));
-    expect(ps3.toString(), equals('ParagraphStyle(textAlign: unspecified, textDirection: unspecified, fontWeight: FontWeight.w700, fontStyle: unspecified, maxLines: unspecified, textHeightBehavior: unspecified, fontFamily: unspecified, fontSize: 12.0, height: 123.0x, ellipsis: unspecified, locale: unspecified)'));
+    expect(ps0.toString(), equals('ParagraphStyle(textAlign: unspecified, textDirection: TextDirection.ltr, fontWeight: unspecified, fontStyle: unspecified, maxLines: unspecified, textHeightBehavior: unspecified, fontFamily: unspecified, fontSize: 14.0, height: unspecified, strutStyle: unspecified, ellipsis: unspecified, locale: unspecified)'));
+    expect(ps1.toString(), equals('ParagraphStyle(textAlign: unspecified, textDirection: TextDirection.rtl, fontWeight: unspecified, fontStyle: unspecified, maxLines: unspecified, textHeightBehavior: unspecified, fontFamily: unspecified, fontSize: 14.0, height: unspecified, strutStyle: unspecified, ellipsis: unspecified, locale: unspecified)'));
+    expect(ps2.toString(), equals('ParagraphStyle(textAlign: TextAlign.center, textDirection: unspecified, fontWeight: FontWeight.w800, fontStyle: unspecified, maxLines: unspecified, textHeightBehavior: unspecified, fontFamily: unspecified, fontSize: 10.0, height: 100.0x, strutStyle: unspecified, ellipsis: unspecified, locale: unspecified)'));
+    expect(ps3.toString(), equals('ParagraphStyle(textAlign: unspecified, textDirection: unspecified, fontWeight: FontWeight.w700, fontStyle: unspecified, maxLines: unspecified, textHeightBehavior: unspecified, fontFamily: unspecified, fontSize: 12.0, height: 123.0x, strutStyle: unspecified, ellipsis: unspecified, locale: unspecified)'));
   });
 }