[web] Unskip tests that are already passing in Safari

lib/web_ui/test/paragraph_test.dart

@@ -56,9 +56,7 @@ void main() async {
         closeTo(paragraph.alphabeticBaseline * kAhemBaselineRatio, 3.0),
       );
     }
-  },
-      // TODO(nurhan): https://github.com/flutter/flutter/issues/50590
-      skip: browserEngine == BrowserEngine.webkit);
+  });
 
   testEachMeasurement('predictably lays out a multi-line paragraph', () {
     for (double fontSize in <double>[10.0, 20.0, 30.0, 40.0]) {
@@ -85,9 +83,7 @@ void main() async {
         closeTo(paragraph.alphabeticBaseline * kAhemBaselineRatio, 3.0),
       );
     }
-  },
-      // TODO(nurhan): https://github.com/flutter/flutter/issues/50590
-      skip: browserEngine == BrowserEngine.webkit);
+  });
 
   testEachMeasurement('predictably lays out a single-line rich paragraph', () {
     for (double fontSize in <double>[10.0, 20.0, 30.0, 40.0]) {
@@ -305,9 +301,7 @@ void main() async {
         TextDirection.rtl,
       ),
     );
-  },
-      // TODO(nurhan): https://github.com/flutter/flutter/issues/50590
-      skip: browserEngine == BrowserEngine.webkit);
+  });
 
   testEachMeasurement(
       'getBoxesForRange return empty list for zero-length range', () {
@@ -427,7 +421,5 @@ void main() async {
 
     expect(paragraph.width, 30);
     expect(paragraph.height, 10);
-  },
-      // TODO(nurhan): https://github.com/flutter/flutter/issues/50590
-      skip: browserEngine == BrowserEngine.webkit);
+  });
 }

lib/web_ui/test/text/measurement_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@TestOn('chrome || firefox')
-
 import 'package:ui/ui.dart' as ui;
 import 'package:ui/src/engine.dart';
 
@@ -31,14 +29,19 @@ typedef MeasurementTestBody = void Function(TextMeasurementService instance);
 
 /// Runs the same test twice - once with dom measurement and once with canvas
 /// measurement.
-void testMeasurements(String description, MeasurementTestBody body) {
+void testMeasurements(String description, MeasurementTestBody body, {
+  bool skipDom,
+  bool skipCanvas,
+}) {
   test(
     '$description (dom)',
     () => body(TextMeasurementService.domInstance),
+    skip: skipDom,
   );
   test(
     '$description (canvas)',
     () => body(TextMeasurementService.canvasInstance),
+    skip: skipCanvas,
   );
 }
 
@@ -383,6 +386,7 @@ void main() async {
           expect(result.lines, isNull);
         }
       },
+      skipDom: browserEngine == BrowserEngine.webkit,
     );
 
     testMeasurements(
@@ -797,6 +801,7 @@ void main() async {
           expect(result.lines, isNull);
         }
       },
+      skipDom: browserEngine == BrowserEngine.webkit,
     );
 
     testMeasurements('respects max lines', (TextMeasurementService instance) {

lib/web_ui/test/text_test.dart

@@ -40,9 +40,7 @@ void main() async {
             from: paragraph.alphabeticBaseline * baselineRatio),
       );
     }
-  },
-      // TODO(nurhan): https://github.com/flutter/flutter/issues/50590
-      skip: browserEngine == BrowserEngine.webkit);
+  });
 
   test('predictably lays out a multi-line paragraph', () {
     for (double fontSize in <double>[10.0, 20.0, 30.0, 40.0]) {
@@ -72,9 +70,7 @@ void main() async {
             from: paragraph.alphabeticBaseline * baselineRatio),
       );
     }
-  },
-      // TODO(nurhan): https://github.com/flutter/flutter/issues/50590
-      skip: browserEngine == BrowserEngine.webkit);
+  });
 
   test('lay out unattached paragraph', () {
     final ParagraphBuilder builder = ParagraphBuilder(ParagraphStyle(