ThinLTO: fix non-determinism in bitcode writing
ThinLTO: fix non-determinism in bitcode writing

Calls are initialized from a DenseMap. We can sort them using the
value id to recover some determinism during serialization.

From: mehdi_amini <mehdi_amini@91177308-0d34-0410-b5e6-96231b3b80d8>

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@269638 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm