to definite the reusing external table by themselves instead of
searching in gpload, which may have bad performance if there are
too many external tables.

- Fix gpload.py, add schema prefix to every external table name
  when EXTERNAL.SCHEMA is set
- Add new test cases

gpload ERROR_TABLE configuration is forbidden in GPDB5 and use
LOG_ERRORS instead. That's why Informatica 9.x connector can't
load data into GPDB5.

So we accept ERROR_TABLE, if ERROR_TABLE is set, we will not
create it as before, but set LOG_ERRORS and REUSE_TABLE to true
instead.

gpload error count is incorrect when more than one segment has format
error, for the cmdtime is different, and only errors with the newest
cmdtime is counted.

So we add startTime which will be used for counting all the errors
occured during the same gpload operation.

Concourse doesn't support AIX natively, we need to clone the repo
with the correspond commit on remote machine, compile the packages,
and download them back to concourse container as output.

Testing client and loader for platform without gpdb server is
another challenge. We setup GPDB server on concourse container just
like most installcheck tests, and use SSH tunnel to forward ports
from and to the remote host. This way both CL tools and GPDB server
feel they are on the same machine, and the test can run normally.

The original gpload test suites is intended to be run locally,
so gpdb cluster and test must be on the same machine.

For platform that doesn't have GPDB server available but have
loader package, we need to run the test remotely.

For subselect_gp test, we were removing the distribution policy of a
table to see if it would do a gather motion or not. Since it's
technically a corrupted table, we should delete it after we're done
with it. We also remove a quicklz reference that should not have been
there.

For gppc test, they were using the regression database. This made our
gpcheckcat call at the end of ICW relatively useless since all our
data would have been deleted due to gppc tests recreating the
regression database.

For gpload test, some generated files were previously commited. We
should be actively cautious of this and remove them when we see them.

0, default database doesn't exist in some env.
1, reports good even the cases failed.
2, init_file ignores too many lines.

This commit fixes these.

Signed-off-by: NMarbin Tan <mtan@pivotal.io>

1. fix an error if the quote and escape options are not specified in the
CSV format.

2. add codes for delimiter, escape and quote options to process a
ASCII, unicode-encoded or escaped single character in order to find
the correct table to reuse when load external data.

The old cdbfast test suite had these, good to move to ICW.