test: add SELECT INTO statement parsing tests #963

Job	Run time
parser-tests (parser)	55s
parser-tests (plpgsql-parser)	1m 1s
parser-tests (pgsql-cli)	59s
parser-tests (deparser)	59s
parser-tests (proto-parser)	56s
parser-tests (transform)	5m 41s
parser-tests (plpgsql-deparser)	1m 6s
parser-tests (traverse)	59s
parser-tests (utils)	1m 1s
	13m 37s

Provide feedback