Improve the sysctl symbol extraction from the kernel so that it find more
(all?) sysctl's.  Previously some where missed, depending on how they were
defined.
MFV r254070:

Merge vendor bugfix for ZFS test suite that triggers false positives.

Illumos ZFS issues:
  3949 ztest fault injection should avoid resilvering devices
  3950 ztest: deadman fires when we're doing a scan
  3951 ztest hang when running dedup test
  3952 ztest: ztest_reguid test and ztest_fault_inject don't place nice together