Cleaned up a few additional commit corner cases

- General cleanup from integration, including cleaning up some older
  commit code
- Partial-prog tests do not make sense when prog_size == block_size
  (there can't be partial-progs!)
- Fixed signed-comparison issue in modified filebd

bd/lfs_filebd.c

@@ -97,7 +97,7 @@ int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
     }
 
     // file truncated? zero for reproducability
-    if (res2 < size) {
+    if ((lfs_size_t)res2 < size) {
         memset((uint8_t*)buffer + res2, 0, size-res2);
     }