[llvm] [ADT] Always use 32-bit size type for SmallVector with 16-bit elements (PR #95536)

[Chelsea Cassanova via llvm-commits]

chelcassanova wrote:

This is also breaking the GreenDragon macOS buildbots: https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/as-lldb-cmake/6522/console

https://github.com/llvm/llvm-project/pull/95536