[ CLI ] Fix issue where test was expecting different error message than

that reported on Windows

Change-Id: Ib907f4d8afd50456ff962a7769a1f79d9b150c87
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/172824
Commit-Queue: Ben Konyi <[email protected]>
Reviewed-by: Alexander Aprelev <[email protected]>

Author: bkonyi

pkg/dartdev/test/no_such_file_test.dart

@@ -31,8 +31,7 @@ void main() {
     p = project();
     final result = p.runSync('--snapshot=abc', ['foo.dart']);
     expect(result.stderr, isNotEmpty);
-    expect(result.stderr,
-        contains("Error when reading 'foo.dart': No such file or directory"));
+    expect(result.stderr, contains("Error when reading 'foo.dart':"));
     expect(result.stdout, isEmpty);
     expect(result.exitCode, 254);
   });