Delete BootPrebuilt.

They are unused.

Test: TH
Change-Id: I2d7353374f8361c4e21a495ab0f0140dfb8c1deb
(cherry picked from commit c551fe0f2e571374e8a088e59d4d55ec383f0612)
Merged-In: I2d7353374f8361c4e21a495ab0f0140dfb8c1deb
1 file changed
tree: 4b825dc642cb6eb9a060e54bf8d69288fbee4904

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