[clang-tools-extra] Initialize value. (PR #122339)

[Tom Honermann via cfe-commits]

tahonermann wrote:

The static analysis tool produced a false positive; I see no reason for a change. The static analyzer failed to recognize that `APValue::Kind` is initialized to `None` during default construction of the `EvalResult` variable and that it can't have changed by the time the variable is destructed. The static analyzer falsely determined that `DestroyDataAndMakeUninit()` could be called from the `APValue` destructor.

https://github.com/llvm/llvm-project/pull/122339