The cri image service init has a bug where, after getting FSPath
for snapshotter_i, it stores it under defaultSnapshotter instead
of snapshotter_i.
Also make a few other refactor:
1. Dedup the snapshotRoot loading for defaultSnapshotter
2. Remove some unnecessary logic in RuntimePlatforms for-loop
Signed-off-by: Jin Dong <djdongjin95@gmail.com>