Sql. Race between getting logical topology and mapping fragments

MappingServiceImpl#nodesSetRef might contain an empty set when mapping if the logical topology event hasn't occurred yet. This results in colocation targets having nodes equal to 0, so no targets are colocated, even if they are supposed to be. This results in 'ColocationMappingException: Targets are not colocated' (thrown in AbstractTarget:123, as of commit b9bd1c4db01a5377190b363c208375d845890265).

This is easily reproducible locally with ItDataSchemaSyncTest#checkSchemasCorrectlyRestore()