[clang] [analyzer] Avoid use of `CallEvent`s with obsolete state (PR #160707)

[Donát Nagy via cfe-commits]

NagyDonat wrote:

I tested this change on a set of open source projects (memcached, tmux, curl, twin, vim, openssl, sqlite, ffmpeg, postgres, tinyxml2, libwebm, xerces, bitcoin, protobuf, qtbase, openrct2) and the set of analyzer findings did not change between the baseline recent main revision and this commit.

Therefore, this commit is probably just code cleanup ("fix logical inconsistency that causes no actual harm") -- but there may be rare corner cases where this change modifies the behavior of the analyzer by ensuring that the some callbacks get a `CallEvent` with up-to-date state.

@steakhal @haoNoQ I think I addressed all the review suggestions and as far as I see this PR is ready to be merged. Please review this when it's convenient for you.

https://github.com/llvm/llvm-project/pull/160707