test_sysctl: Fix test metadata getters

The functions get_test_{count,enabled,target} use awk to get the N'th
field in the ALL_TESTS variable. A variable with leading zeros (e.g.
0009) is misinterpreted as an entire line instead of the N'th field.
Remove the leading zeros so this does not happen. We can now use the
helper in tests 6, 7 and 8.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>