[clang] [analyzer] Model Microsoft "__assume" in the same way as clang "__builtin_assume" (PR #80456)

[Balazs Benics via cfe-commits]

steakhal wrote:

Pushed manually to preserve the patch author.
(I believe, "squash&merge" would overwrite it.)

Merged as ae354c5a45d319b3117c2822b8f6988461f3cb33.

https://github.com/llvm/llvm-project/pull/80456