Revert r340096: 9952 Block size change during zfs receive drops spill block

It was reported, and I easily reproduced it, that this change triggers panic
when receiving replication stream with enabled embedded blocks, when short
file compressing into one embedded block changes its block size. I am not
sure that the problem is in this particuler patch, not just triggered by it,
but since investigation and fix will take some time, I've decided to revert
this for now.

PR: 198457, 233277