HPCC-12675 Prevent Regression Test Engine hangs when ecl command hangs.

Fix timeout handling problem when the suite executed sequentally.

Fix source merge problem impacted to suite.py

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>
Merge pull request #6739 from AttilaVamos/HPCC-12675-improvement

HPCC-12675 Prevent Regression Test Engine hangs when ecl command hangs.

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>