Fix some test issues in VirtualFileSystemTest

Use camel-case names, remove some dead code, and fix a copy-and-pasted test.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201691 91177308-0d34-0410-b5e6-96231b3b80d8
Updated tutorial code according to the changes in r197139.

Thanks to Konrad Kleine for reporting the inconsistency!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201693 91177308-0d34-0410-b5e6-96231b3b80d8
Reduce verbosity in the virtual file system using LLVM.h

No functional change

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201696 91177308-0d34-0410-b5e6-96231b3b80d8