Tests: strengthen CHECK line to avoid picking up stray path.
Tests: strengthen CHECK line to avoid picking up stray path.

A bot had "-LTO" in its working directory, which matched the regex used in this
test. Since the arg is quoted, we can exploit that instead. Still broken if
there's a path with a quote in, but I think that's pretty niche.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@302066 91177308-0d34-0410-b5e6-96231b3b80d8

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