remove unneeded envvars

Author: glasnt

cloud-sql/sqlserver/mssql/ci-setup.json

@@ -2,9 +2,7 @@
     "env": {
       "INSTANCE_HOST": "127.0.0.1",
       "INSTANCE_CONNECTION_NAME": "nodejs-docs-samples-tests:us-central1:sql-server-ci",
-      "UNIX_SOCKET_DIR": "tmp/cloudsql",
       "CLOUD_SQL_CONNECTION_NAME": "$INSTANCE_CONNECTION_NAME",
-      "INSTANCE_UNIX_SOCKET": "$UNIX_SOCKET_DIR/$INSTANCE_CONNECTION_NAME",
       "DB_NAME": "kokoro_ci",
       "DB_USER": "kokoro_ci"
     },