ThinLTO: Fix Gold test after caching fix in r283655
ThinLTO: Fix Gold test after caching fix in r283655

(I don't have Gold available, so this is speculative)

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@283681 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm