HPCC-9528 Regression Suite won't work with relative suiteDir path

Add a new class to expand and check relative path.

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>
Merge pull request #4542 from AttilaVamos/HPCC-9528-fix

HPCC-9528 Regression Suite won't work with relative suiteDir path

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>