BIGTOP-953. Revert BIGTOP-835 and BIGTOP-950.

Revert

"BIGTOP-950. race condition for output consumption in Shell code"
"BIGTOP-835. The shell exec method must have variants which have timeout and can run in background"

This reverts commits
 bc49df0bf3ed71dbe7a8ded7857b6087d4df8fd0
 b5f900efc17c616dc34704cd520285adcd814e9e
Merge remote-tracking branch 'public/master' into trunk