Pull all of the internal debug infrastructure up in to the zfs
code to clean up the layering. Remove all the dodgy usage of
SET_ERROR and DTRACE_PROBE from the spl. Luckily it was
lightly used in the spl layer so we're not losing much.
Sponsored-by: https://despairlabs.com/sponsor/
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#17861
