Add seek+read and seek+write to same file testcases

We had seek+read and seek+write to different files but not
this one.

Signed-off-by: Anton Blanchard <anton@samba.org>
Pass the number of tasks to run into testcase_prepare

Tests might size resources based on the number of tasks
being run, so pass it into testcase_prepare.

Signed-off-by: Anton Blanchard <anton@samba.org>
Pass the task number into testcase

Tests might need to know the task number so they can separate
access to a resource (eg offsets into a file).

Signed-off-by: Anton Blanchard <anton@samba.org>
Add pwrite and pread tests that operate on different offsets in the file

pread2/pwrite2 hit the same offset in the file, these tests
are arguably a little more realistic.

Signed-off-by: Anton Blanchard <anton@samba.org>
Rename readseek and writeseek

Now we have multiple seek tests, rename these to match the other
tests.

Signed-off-by: Anton Blanchard <anton@samba.org>
Add read+seek and write+seek tests that operate on different offsets in the file

readseek2/writeseek2 hit the same offset in the file, these tests
are arguably a little more realistic.

Signed-off-by: Anton Blanchard <anton@samba.org>