VtsBootconfigTest: enforce requirement from U+

This is relanding https://r.android.com/3319737 after it was reverted
due to using an undefined __ANDROID_APU_U__.

Test: none
Bug: 376290434
Bug: 401466862
Merged-In: I3012fff70eb8a27bb81aab056817d72ac559f8d2
Change-Id: I09cd0b26bf2989e39d269da3903bf5d3acbe33f5