[analyzer] Fix a bug in unexplored_first_location_queue iteration order.
[analyzer] Fix a bug in unexplored_first_location_queue iteration order.

Pointed out by Artem in post-commit review for https://reviews.llvm.org/D53058

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@344322 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 4453d65072d287f82b985827be49fe265fd2660f)

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