[preprocessing record] Add some sanity checks for the preprocessed entity index to make sure we don't crash on release if the index is not valid.
[preprocessing record] Add some sanity checks for the preprocessed entity index
to make sure we don't crash on release if the index is not valid.

rdar://13089714

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@175010 91177308-0d34-0410-b5e6-96231b3b80d8

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