1. Minor fixes for cardinality estimation of unpartitioned tables.
2. Reworks handling of corrupt table stats as follows:
The stats of a table or partition are reported as corrupt if the
numRows < -1, or if numRows == 0 but the table size is positive.
3. Removes the Preconditions check reported in IMPALA-1657 in favor
or issuing a corrupt table stats warning.
4. Fixes a few tests to set numRows together with
STATS_GENERATED_VIA_STATS_TASK so that the numRows is definitely
set in the HMS.
Change-Id: I1d3305791d96e1c23a901af7b7c109af9352bb44
Reviewed-on: http://gerrit.cloudera.org:8080/4166
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: Internal Jenkins
12496c7fbf