Revert^3 "Boot image extension."

This reverts commit 02820f424714e711bbd4cb4b04a109416eb0c8b8.
Also reverts commit beb66b38dcce937d7eee9ef2d07b6402c720f8ee
that contained a follow-up fix.

Reason for revert: b/144001974

Bug: 119800099
Bug: 143492855
Bug: 144001974
Change-Id: I4da5330c3efa9f0c3508e85344c031d3b360ca0a
12 files changed