Enable build verification with race (#8583)

buildscripts/gateway-tests.sh

@@ -24,7 +24,7 @@ function start_minio_server()
     MINIO_ACCESS_KEY=minio MINIO_SECRET_KEY=minio123 \
                     minio --quiet --json server /data --address 127.0.0.1:24242 > server.log 2>&1 &
     server_pid=$!
-    sleep 3
+    sleep 10
 
     echo "$server_pid"
 }
@@ -35,7 +35,7 @@ function start_minio_gateway_s3()
                     minio --quiet --json gateway s3 http://127.0.0.1:24242 \
                     --address 127.0.0.1:24240 > gateway.log 2>&1 &
     gw_pid=$!
-    sleep 3
+    sleep 10
 
     echo "$gw_pid"
 }