HdfsTable.toMinimalTCatalogObject() not always collect the partitions

This is a follow-up task of IMPALA-12831 where we try acquiring the table read lock in HdfsTable.toMinimalTCatalogObject() to protect the access. If acquiring the table read lock fails, we return the object without the partitions.

There is a WIP patch for adding a fine-grained lock on the partition map to improve this: https://gerrit.cloudera.org/c/21115/