The string parsing code already errors if the decimal column either
overflows or underflows (i.e. loses scale). Let's just add a test
case.
Change-Id: Idd66c0fb5a4d201919d39f73dea08b87339d6469
Reviewed-on: http://gerrit.cloudera.org:8080/6150
Reviewed-by: Dan Hecht <dhecht@cloudera.com>
Tested-by: Impala Public Jenkins