c-index-test: Don't leak diagnostic category text.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208503 91177308-0d34-0410-b5e6-96231b3b80d8
Driver: Don't leak the -Xarch argument when its use is incorrect.

(LLVM's lib/Option looks like it might appreciate being hit with the
std::unique_ptr stick.)


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208505 91177308-0d34-0410-b5e6-96231b3b80d8