ZTS: zdb_block_size_histogram increase variance
The expected variance for this test case was originally set at 10%
based on local testing. Additional testing via the CI has show it
can be as large as 11%. Increase the expected maximum to 12% to
prevent this test from incorrectly failing.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11148