test/timeout: fix exec-target naming
test/timeout: fix exec-target naming

A previous commit renamed all test targets to foo.t, but didn't update
the timeout test case. Hence it now tries to exec something that isn't
there and rightfully complains about it:

Running test timeout.t                                              Can't find exec-target, skipping

Update the test to use the right target.

Fixes: f200b5bba701 ("test/Makefile: Append `.t` to the test binary")
Signed-off-by: Jens Axboe <cd8c6775e60d6f67a6984377324e5290df3d5358@kernel.dk>

axboe/liburing,axboe/liburing,axboe/liburing