Properly handle the case of timeout when running LTP

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Better support for LTP customization

Allow invoker to specify list of tests to run via TA_LTP_TESTS_TO_RUN.

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>