[9.18] Revert "Kill unit tests that run more than 1200 seconds"

This reverts commit 6cdeb5b0 which added wrapper around all the unit tests that would run the unit test in the forked process.

This makes any debugging of the unit tests too hard. Futures attempts to fix #3980 (closed) (closed) should add a custom automake test harness (log driver) that would kill the unit test after configured timeout.

Closes #3980 (closed)

Backport of MR !7833 (merged)