failure on the appveyor bot in analyze-sample-code.dart when deleting a temp dir #17484
Description
I see a (possibly intermittent?) failure on the windows bot:
Unhandled exception:
FileSystemException: Deletion failed, path = 'C:\Users\appveyor\AppData\Local\Temp\1\analyze_sample_code_ae05eda9-5494-11e8-81e7-00155dfb5a77' (OS Error: The process cannot access the file because it is being used by another process.
, errno = 32)
#0 _Directory._deleteSync (dart:io/directory_impl.dart:174:7)
#1 FileSystemEntity.deleteSync (dart:io/file_system_entity.dart:463:47)
#2 main (file:///C:/projects/flutter%20sdk/dev/bots/analyze-sample-code.dart:297:12)
<asynchronous suspension>
#3 _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:279:19)
#4 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:165:12)
We may need to catch and ignore exceptions deleting the temp dir in dev/bots/analyze-sample-code.dart:297.