Disable GroupCommitTest in Appveyor (#4536)

Summary:
We have already disabled it on Travis since it has been too flaky. The same problem arises in Appveyor as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4536

Differential Revision: D10452240

Pulled By: maysamyabandeh

fbshipit-source-id: 728f4ecddf780097159dc0a0737d460eb5ce4f09

db/db_test.cc

@@ -2313,6 +2313,9 @@ INSTANTIATE_TEST_CASE_P(
 #endif  // ROCKSDB_LITE
 
 // Group commit test:
+#if !defined(TRAVIS) && !defined(OS_WIN)
+// Disable this test temporarily on Travis and appveyor as it fails
+// intermittently. Github issue: #4151
 namespace {
 
 static const int kGCNumThreads = 4;
@@ -2339,9 +2342,6 @@ static void GCThreadBody(void* arg) {
 
 }  // namespace
 
-#ifndef TRAVIS
-// Disable this test temporarily on Travis as it fails intermittently.
-// Github issue: #4151
 TEST_F(DBTest, GroupCommitTest) {
   do {
     Options options = CurrentOptions();