[web] Unskip assertions test. Update for latest stack trace format. (#53795)

packages/flutter/lib/src/foundation/assertions.dart

@@ -926,6 +926,7 @@ void debugPrintStack({StackTrace stackTrace, String label, int maxFrames}) {
     // is addressed.
     lines = lines.skipWhile((String line) {
       return line.contains('StackTrace.current') ||
+             line.contains('dart-sdk/lib/_internal') ||
              line.contains('dart:sdk_internal');
     });
   }

packages/flutter/test/foundation/assertions_test.dart

@@ -14,7 +14,7 @@ void main() {
     });
     expect(log[0], contains('Example label'));
     expect(log[1], contains('debugPrintStack'));
-  }, skip: isBrowser);
+  });
 
   test('debugPrintStack', () {
     final List<String> log = captureOutput(() {
@@ -39,7 +39,7 @@ void main() {
 
     expect(joined, contains('captureOutput'));
     expect(joined, contains('\nExample information\n'));
-  }, skip: isBrowser);
+  });
 
   test('FlutterErrorDetails.toString', () {
     expect(