The FileCheck utility is enhanced to support a `--ignore-case`
option. This is useful in cases where the output of Unix tools
differs in case (e.g. case not specified by Posix).
Reviewers: Bigcheese, jakehehrlich, rupprecht, espindola, alexshap, jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D68146
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374538 91177308-0d34-0410-b5e6-96231b3b80d8