[LIT] Handle xml characters in test names

Lit creates malformed xml when the test case has an & in the name.

Escape those correctly.

This also adds a test case which I will add other nasty encoding issues to in some followup commits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331942 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed