ztest: ztest_dsl_prop_set_uint64() ENOSPC consistency
It is possible for ztest_dsl_prop_set_uint64() to fail with ENOSPC
and this needs to be handled consistently.
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #14351