Do not shadown err within MSSQL test container intialization (#28468)

- Get better test failure error messages by not shadowing the errors
   when we are attempting to start the MSSQL docker container, so
   we can fail the tests with the proper error message that is occuring
   instead of mssqlhelper.go:60: Could not start docker MSSQL: %!s(<nil>)

helper/testhelpers/mssql/mssqlhelper.go

@@ -35,7 +35,8 @@ func PrepareMSSQLTestContainer(t *testing.T) (cleanup func(), retURL string) {
 	var err error
 	for i := 0; i < numRetries; i++ {
 		var svc *docker.Service
-		runner, err := docker.NewServiceRunner(docker.RunOptions{
+		var runner *docker.Runner
+		runner, err = docker.NewServiceRunner(docker.RunOptions{
 			ContainerName: "sqlserver",
 			ImageRepo:     "mcr.microsoft.com/mssql/server",
 			ImageTag:      "2017-latest-ubuntu",
@@ -48,7 +49,8 @@ func PrepareMSSQLTestContainer(t *testing.T) (cleanup func(), retURL string) {
 			},
 		})
 		if err != nil {
-			t.Fatalf("Could not start docker MSSQL: %s", err)
+			t.Logf("Could not start docker MSSQL: %v", err)
+			continue
 		}
 
 		svc, err = runner.StartService(context.Background(), connectMSSQL)
@@ -57,7 +59,7 @@ func PrepareMSSQLTestContainer(t *testing.T) (cleanup func(), retURL string) {
 		}
 	}
 
-	t.Fatalf("Could not start docker MSSQL: %s", err)
+	t.Fatalf("Could not start docker MSSQL: %v", err)
 	return nil, ""
 }