Thread Safety Analysis: Fix DenseMap iterator invalidation UAF
Thread Safety Analysis: Fix DenseMap iterator invalidation UAF

Rather than storing BeforeInfo in the DenseMap by value, this stores a
unique_ptr to it, so that we can keep a pointer to it live across
subsequent DenseMap insertions.

This change also removes the unique_ptr wrapper around BeforeVect
because now we're indirecting at a higher level.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@253694 91177308-0d34-0410-b5e6-96231b3b80d8

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