cpu: Add support to checker for CACHE_BLOCK_ZERO commands.
cpu: Add support to checker for CACHE_BLOCK_ZERO commands.

The checker didn't know how to properly validate these new commands.
(transplanted from 38c7a9ea77299e4b7c20bb670922af6015b9f591)

LingxiaoJIA/gem5,LingxiaoJIA/gem5,LingxiaoJIA/gem5,LingxiaoJIA/gem5,LingxiaoJIA/gem5,LingxiaoJIA/gem5,LingxiaoJIA/gem5