Make the test runner output look pretty and show test duration to make
it visible which tests take the longest time to run.  The output looks
as follows now:

    TEST tst-af-local.so           OK  (3.288 s)
    TEST tst-bdev-write.so         OK  (1.058 s)
    TEST tst-bsd-evh.so            OK  (1.071 s)
    TEST tst-bsd-kthread.so        OK  (1.234 s)
    TEST tst-bsd-taskqueue.so      OK  (1.062 s)
    TEST tst-bsd-tcp1.so           OK  (2.114 s)
    TEST tst-commands.so           OK  (1.141 s)
    TEST tst-condvar.so            OK  (1.776 s)
    TEST tst-dns-resolver.so       OK  (2.560 s)
    TEST tst-epoll.so              OK  (1.952 s)
    TEST tst-except.so             OK  (1.146 s)
    TEST tst-fpu.so                OK  (2.630 s)
    TEST tst-fs-link.so            OK  (1.051 s)
    TEST tst-fs-stress.so          OK  (1.027 s)
    TEST tst-fsx.so                OK  (1.067 s)
    TEST tst-hub.so                OK  (6.256 s)
    TEST tst-huge.so               OK  (2.199 s)
    TEST tst-kill.so               OK  (4.147 s)
    TEST tst-libc-locking.so       OK  (2.110 s)
    TEST tst-loadbalance.so        OK  (1.070 s)
    TEST tst-mmap-file.so          OK  (1.080 s)
    TEST tst-mmap.so               OK  (1.087 s)
    TEST tst-pipe.so               OK  (7.306 s)
    TEST tst-preempt.so            OK  (1.119 s)
    TEST tst-pthread.so            OK  (1.100 s)
    TEST tst-queue-mpsc.so         OK  (3.748 s)
    TEST tst-ramdisk.so            OK  (1.078 s)
    TEST tst-readdir.so            OK  (1.094 s)
    TEST tst-remove.so             OK  (1.030 s)
    TEST tst-rename.so             OK  (1.157 s)
    TEST tst-resolve.so            OK  (1.095 s)
    TEST tst-scheduler.so          OK  (1.087 s)
    TEST tst-sleep.so              OK  (3.083 s)
    TEST tst-solaris-taskq.so      OK  (1.061 s)
    TEST tst-stat.so               OK  (1.106 s)
    TEST tst-strerror_r.so         OK  (1.102 s)
    TEST tst-tcp-sendonly.so       OK  (2.014 s)
    TEST tst-tcp.so                OK  (1.080 s)
    TEST tst-threadcomplete.so     OK  (2.770 s)
    TEST tst-tracepoint.so         OK  (1.109 s)
    TEST tst-truncate.so           OK  (1.083 s)
    TEST tst-utimes.so             OK  (1.079 s)
    TEST tst-vblk.so               OK  (1.310 s)
    TEST tst-vfs.so                OK  (1.118 s)
    TEST tst-yield.so              OK  (1.992 s)
    TEST tst-zfs-mount.so          OK  (1.087 s)
  OK (58 tests run, 82.944 s)

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>