[clang] [clang][AST] Added assert to prevent infinite recursion in computing layout (PR #154134)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Because this can be hit by user-written expressions, I think an assert is actually the wrong fix; we should handle it gracefully. Otherwise, in asserts builds this is effectively a crash and in non-asserts builds it's still an infinite recursion.

CC @JDevlieghere @Michael137 for other opinions on the lldb side

https://github.com/llvm/llvm-project/pull/154134