Pre-reserve space for unique ID input calculation

Reduce the number of (assumed infallible) allocations involved in
building the input for UNIQUE_ID calculation.

Bug: 260520522
Bug: 260347665
Bug: 258358961
Test: VtsAidlKeyMintTargetTest
Change-Id: I1b5def69cf20167f309f1f381998367f78a3439d
1 file changed