Strengthen cfi-check-fail test.
Strengthen cfi-check-fail test.

r258993 allows stricter testing for basic block labels by making
sure that they are always followed by ":". Use this to improve the
test.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@258997 91177308-0d34-0410-b5e6-96231b3b80d8

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