[Analysis] Restore the call to reserve (#136215)
commit 47d8fec9b8bd5425af17711317a41743a30a8cef
Author: Kazu Hirata <kazu@google.com>
Date: Wed Apr 16 19:30:01 2025 -0700
has removed the call to reserve here. This patch restores it as
std::vector::insert, called by llvm::append_range, may not be able to
deduce the size of the range. For example, std::vector in libc++
distinguishes has two versions of std::vector::insert depending on
whether the iterator is an input iterator or a foward iterator.
