[clang] [CIR] Upstream lowering of conditional operators to TernaryOp (PR #138156)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

Whew... this ends up being a sizable patch.  I know you tried to break it up, but it is still pretty significant.

I have a couple of comments as drive-bys, else I'll let others do the approvals.

https://github.com/llvm/llvm-project/pull/138156