swift234

Improve checking of protocol-conformance requirements for generic
types in a few ways:
  - Actually check the extra requirements placed on associated types,
  e.g., "T.Element : Ordered"
  - Actually encode/store the protocol conformance information for a
  BoundGenericType in the same way that we do for SpecializeExpr,
  GenericMemberRefExpr, and GenericSubscriptExpr. Yay, consistency.
  - Move the storage for the protocol conformance information into a
  DenseMap in the ASTContext indexed by canonical BoundGenericType, so
  it doesn't require inline storage in BoundGenericType.


Swift SVN r2517