Fix the windows bot

The CL https://dart-review.git.corp.google.com/c/sdk/+/505045 broke the
windows bot because the file path is different. It's different by more
than just the path separator, and given that the point of the test isn't
to ensure that the right file path is being printed, I decided to
remove the file path check from the expectations.

Change-Id: Ie5aef4beddb2051c63b2d1686664afb8841297fa
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/505383
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Samuel Rawlins <srawlins@google.com>

pkg/dartdev/test/commands/fix_test.dart

@@ -345,7 +345,6 @@ linter:
       expect(
         result.stdout,
         stringContainsInOrderWithVariableBullets([
-          'lib/main.dart',
           'prefer_single_quotes - 1 fix',
           '1 fix made in 1 file.',
         ]),