swift234

SIL: Capture generic parameters through nested closures.

We were failing to capture generic parameters from closure contexts that themselves capture generic parameters from context. This fixes <rdar://problem/15417783>. While we're here, eliminate some unnecessary splitting of 'ClosureExpr' and 'AutoClosureExpr' in the SILDeclRef::Loc PointerUnion; we can just use their base class AbstractClosureExpr in the PointerUnion.

Swift SVN r10031