Renamed crystallize_size -> crystal_size

The original name was a bit of a mouthful.

Also dropped the default crystal_size in the test/bench runners
block_size/4 -> block_size/8. I'm already noticing large amounts of
inflation when blocks are fragmented, though I am experimenting with a
rather small fragment_size right now.

Future benchmarks/experimentation is required to figure out good values
for these.

lfs.c

@@ -10592,7 +10592,7 @@ static int lfsr_file_flushshrub(lfs_t *lfs, lfsr_file_t *file) {
         // holes we don't account for, but we generally don't want a bunch of
         // small holes in our files anyways.
         //
-        if (right_align - left_align > lfs->cfg->crystallize_size) {
+        if (right_align - left_align > lfs->cfg->crystal_size) {
             // allocate a new block
             lfs_block_t block;
             int err = lfs_alloc(lfs, &block);