[clang] [alpha.webkit.UncountedCallArgsChecker] Don't assume local variables are safe & treat guarded local variable as safe function arguments (PR #82305)

[Ryosuke Niwa via cfe-commits]

rniwa wrote:

So this PR turned out to be not really correct because we can't get rid of local variable checker when calling a non-trivial function.

https://github.com/llvm/llvm-project/pull/82305