[dartdev] Fix expected EOLs in some tests to prevent Windows failures

Not sure why these tests seemed to have only recently started failing, because `print` is documented as using `\r\n` on Windows so it seems like these should have always failed.

Fixes #61227

Change-Id: Ib5018394186583ae37fc17b51ec5ce4d25617494
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/443300
Commit-Queue: Ben Konyi <[email protected]>
Reviewed-by: Ben Konyi <[email protected]>
Reviewed-by: Liam Appelbe <[email protected]>
Auto-Submit: Danny Tuppeny <[email protected]>

Author: DanTup

pkg/dartdev/test/commands/run_test.dart

@@ -55,6 +55,9 @@ void main() {
 }
 ''';
 
+/// The expected EOL from [print] statements.
+final eol = Platform.lineTerminator;
+
 void Function(String) onVmServicesData(
   TestProject p, {
   bool expectDevtoolsMsg = true,
@@ -232,7 +235,7 @@ void run() {
     ]);
 
     // --enable-experiment and main.dart should not be passed.
-    expect(result.stdout, equals('[argument1, argument2]\n'));
+    expect(result.stdout, equals('[argument1, argument2]$eol'));
     expect(result.stderr, isEmpty);
     expect(result.exitCode, 0);
   });
@@ -281,7 +284,7 @@ void main(List<String> args) => print("$b $args");
 
     // --enable-experiment and main.dart should not be passed.
     expect(result.stderr, isEmpty);
-    expect(result.stdout, equals('[--argument1, argument2]\n'));
+    expect(result.stdout, equals('[--argument1, argument2]$eol'));
     expect(result.exitCode, 0);
   });
 
@@ -299,7 +302,7 @@ void main(List<String> args) => print("$b $args");
 
     // --enable-experiment and main.dart should not be passed.
     expect(result.stderr, isEmpty);
-    expect(result.stdout, equals('[--argument1, argument2]\n'));
+    expect(result.stdout, equals('[--argument1, argument2]$eol'));
     expect(result.exitCode, 0);
   });
 
@@ -661,25 +664,25 @@ main() => print('b:b');
             .run(['run', 'a'], workingDir: path.join(p.dirPath, 'pkgs', 'a')),
         isA<ProcessResult>()
             .having((r) => r.exitCode, 'exitCode', 0)
-            .having((r) => r.stdout, 'stdout', 'a:a\n'));
+            .having((r) => r.stdout, 'stdout', 'a:a$eol'));
     expect(
         await p
             .run(['run', 'a:a'], workingDir: path.join(p.dirPath, 'pkgs', 'a')),
         isA<ProcessResult>()
             .having((r) => r.exitCode, 'exitCode', 0)
-            .having((r) => r.stdout, 'stdout', 'a:a\n'));
+            .having((r) => r.stdout, 'stdout', 'a:a$eol'));
     expect(
         await p.run(['run', ':tool'],
             workingDir: path.join(p.dirPath, 'pkgs', 'a')),
         isA<ProcessResult>()
             .having((r) => r.exitCode, 'exitCode', 0)
-            .having((r) => r.stdout, 'stdout', 'a:tool\n'));
+            .having((r) => r.stdout, 'stdout', 'a:tool$eol'));
     expect(
         await p
             .run(['run', 'b'], workingDir: path.join(p.dirPath, 'pkgs', 'a')),
         isA<ProcessResult>()
             .having((r) => r.exitCode, 'exitCode', 0)
-            .having((r) => r.stdout, 'stdout', 'b:b\n'));
+            .having((r) => r.stdout, 'stdout', 'b:b$eol'));
   });
 
   group('DDS', () {