Assert message:
[ 2286.792536] VERIFY3(dptr != NULL) failed (0000000000000000 != 0000000000000000)
[ 2286.793302] PANIC at spl-kmem.c:453:spl_kmem_free_track()

Built with configure options:
./configure --enable-debug --enable-debuginfo --enable-debug-kmem
--enable-debug-kmem-tracking

Use raidz row instead of raidz map pointer as argument for generation
and reconstruction functions. Restore Makefiles on both user/kernel
sides. Export raidz expanded map alloc function for future usage.

Add more functional/raidz test cases to test raidz expansion logic.

Add additional input flags to test expanded raidz map functionality.
Flag -e - select to use expanded version of map alloc function.
Flag -r - set expansion (reflow) offset. The default value is chosen
as -1 (uint max), what mean max reflow offset, case when raidz map
alloc function works in expanded mode.