swift234

IRGenSIL: Improve Explosion handling.

Instead of embedding Explosions in IRGenSIL's LoweredValues and trying to use them directly, store an unmanaged vector of llvm::Value*s, and create Explosions as needed. This allows Explosion APIs to behave normally (consuming values out of the explosion) without potentially messing up SIL value-to-LLVM value mappings.

Swift SVN r4309