[Fuzz] Update download script to support Fuzzilli corpora Based on the arch parameter passed in, download Fuzzilli corpora of the respective arch, and unzip that under the download dir. Bug: 395162693 Change-Id: Ic241fd810ed54db2c7ecfe50436eaf257a41abc1 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6245078 Commit-Queue: Weizhong Xia <[email protected]> Reviewed-by: Ben Reich <[email protected]> Cr-Commit-Position: refs/heads/main@{#1418788} NOKEYCHECK=True GitOrigin-RevId: aac4a67aaf9837ab1cc61e643c899619e90802b9