tests: Don't check return code on timed out tests
tests: Don't check return code on timed out tests

Reason is we shell out to run tests and the shell's return code is not
related to the tests's return code. In other words, when we
SIGTERM/SIGKILL the shell, the shell won't exit cleanly.

iovisor/bpftrace,iovisor/bpftrace,iovisor/bpftrace,iovisor/bpftrace