tests/vb2_avb_tests.c: add key validation tests This commit adds tests cases for AVB key validation callback. New *.avb keys were added to repo, which were created by: avbtool extract_public_key --key <key.pem> --output <key.avb> BUG=b:399607322 TEST=USE_AVB=1 make runtests TEST=FEATURES=test emerge-brya vboot_reference TEST=cros_workon_make --board=brya vboot_reference --test TEST=cros_run_unit_tests --board brya --packages vboot_reference BRANCH=main Cq-Depend: chromium:7198663 Change-Id: I6ebad0987fc50b31a5b4a1002edce2c79fae6030 Signed-off-by: Grzegorz Bernacki <[email protected]> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/7146233 Commit-Queue: ChromeOS Auto Retry <[email protected]> Reviewed-by: Yu-Ping Wu <[email protected]>