[clang] [analyzer] Fix crash in PaddingChecker on dependent field types (PR #232986)

[Jared Wyles via cfe-commits]

jaredwy wrote:

I think your check is correct. I think your comment is not. Dependent types can have layout T&& for example.

However, I suspect this is a bug in SEMA. It appears that the lambda stays LDK_Unknown. If so, Sema probably should treat it as dependent, and this checker guard could become a defensive backstop. A FIXME pointing at the issue inside ActOnLambdaExpressionAfterIntroducer would be good. As well as a github issue maybe? 

https://github.com/llvm/llvm-project/pull/232986