[clang] [Clang][ExprConst] Handle APValue::LValue in BitCast (PR #184865)

[Tommy Chiang via cfe-commits]

oToToT wrote:

I agree `array.cpp:711:10: note: constexpr bit cast involving type 'long' is not yet supported` looks weird, but I don't see an easy fix here. I can add a FIXME comment to ack the issue in the code. WDYT?

https://github.com/llvm/llvm-project/pull/184865