Sema: use new `getNS{,U}IntegerType` for NS{,U}Integer
Sema: use new `getNS{,U}IntegerType` for NS{,U}Integer

Use the new helper methods to get the underlying type for NSUInteger,
NSInteger types.  This avoids spreading the knowledge of the underlying
types in various sites.  For non-LLP64 targets, this has no change.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@316013 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang