Revamp RegionStoreManager::RemoveDeadBindings.  This method now does a complete mark-and-sweep of the store, removing dead regions and recording the set of live and dead symbols appropriately.
Revamp RegionStoreManager::RemoveDeadBindings.  This method now does a complete mark-and-sweep of the store, removing dead regions and recording the set of live and dead symbols appropriately.


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@60523 91177308-0d34-0410-b5e6-96231b3b80d8

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