[StaticAnalyzer] LoopUnrolling - Attempt #2 to fix a crash in r309006.
[StaticAnalyzer] LoopUnrolling - Attempt #2 to fix a crash in r309006.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@309061 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit e49d5153e8960628ea65106e7182ce52770f92bb)

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