NFCI, optimize layout of FileEntry
NFCI, optimize layout of FileEntry

The reordering of the UID field makes the size of a
FileEntry 8 bytes smaller on 64bit platforms.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@367371 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 321bac621ed3cf88fdb4c157fb9e82b7dbad7b47)

apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang