[llvm-branch-commits] [ADT][NFC] Add missing #include <vector> (#165068) (PR #165074)

[Vitaly Buka via llvm-branch-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/165074

Added in #164524. Fails when using libc++ in a mode that prunes
transitive headers.