Revert "[Modules] Make header inclusion order from umbrella dirs deterministic"
Revert "[Modules] Make header inclusion order from umbrella dirs deterministic"

Reverts commit r289478.

This broke
http://lab.llvm.org:8011/builders/clang-ppc64be-linux/builds/2070
(and maybe
http://lab.llvm.org:8011/builders/clang-x86_64-linux-selfhost-modules-2/builds/2246)

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@289494 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang