Add 'LoadAndVerifyGkiBootImage()'

Load a boot image into memory and checks its integrity rigorously.

This helper does several things:
1. Loads the boot image into memory.
2. Check the integrity of the GKI certificate. (boot_signature)
3. Check that the AVB property descriptors in the GKI certificate are
   consistent with the property descriptors in the image vbmeta footer.

Bug: 211741246
Test: atest vts_gki_compliance_test -v
Change-Id: I3a05078018b33034d1b541d01ee00900394d75e6
1 file changed