Fix name collisions when same table is source & sink

[jogrogan]

When the same table is used as source and sink we are generating statements like:

CREATE TABLE IF NOT EXISTS `ADS`.`AD_CLICKS` (...) WITH ('connector'='datagen', ...);
CREATE TABLE IF NOT EXISTS `ADS`.`AD_CLICKS` (...) WITH ('connector'='blackhole');
INSERT INTO `ADS`.`AD_CLICKS` SELECT * FROM `ADS`.`AD_CLICKS`;

When Flink sees this it fails because ADS.AD_CLICKS has conflicting definitions.

This change will rewrite the query as such:

CREATE TABLE IF NOT EXISTS `ADS`.`AD_CLICKS_source` (...) WITH ('connector'='datagen', ...);
CREATE TABLE IF NOT EXISTS `ADS`.`AD_CLICKS_sink` (...) WITH ('connector'='blackhole');
INSERT INTO `ADS`.`AD_CLICKS_sink` SELECT * FROM `ADS`.`AD_CLICKS_source`;

This change also fixes a Quidem issue where tests run after !specify were failing because the connection was closed

[ryannedolan]

neat!