[clang] [llvm] [clang][llvm] Remove "implicit-section-name" attribute (PR #87906)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

I'd suggest adding bitcode upgrade if it isn't too hard (I don't think it should be?)

Otherwise looks fine.

https://github.com/llvm/llvm-project/pull/87906