May cause infinite loop when initializing rel-cache contains partitioned table

The function of initializing rel-cache is RelationCacheInitializePhase3 and in src/backend/utils/cache/relcache.c file.
When initializing the partition description information, we forget to check if partition key or descriptor is NULL.
Therefore, after the loop restarts, the partition information will be initialized again, resulting in an infinite loop.
Code:
/*
* Reload partition key and descriptor for a partitioned table.
*/
if (relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
{
RelationBuildPartitionKey(relation);
Assert(relation->rd_partkey != NULL);

RelationBuildPartitionDesc(relation);
Assert(relation->rd_partdesc != NULL);

restart = true;
}