[clang] Fix a bug that reports UTF32 (LE) files as UTF16 (LE) ones
[clang] Fix a bug that reports UTF32 (LE) files as UTF16 (LE) ones

Also fix a typo for the SCSU byte order mark.

Differential Revision: https://reviews.llvm.org/D61628

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@360256 91177308-0d34-0410-b5e6-96231b3b80d8

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