Fix SpecificBumpPtrAllocator iteration.
Fix SpecificBumpPtrAllocator iteration.

Need to start from (char*)(Slab+1), and not from (char*)Slab+1.
This fixes crashes in Win64 debug mode.
Thanks to Nicolas Capens!


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@100184 91177308-0d34-0410-b5e6-96231b3b80d8

chubbymaggie/asap,llvm-mirror/llvm,llvm-mirror/llvm,chubbymaggie/asap,dslab-epfl/asap,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,chubbymaggie/asap,apple/swift-llvm,dslab-epfl/asap,llvm-mirror/llvm,apple/swift-llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,apple/swift-llvm,chubbymaggie/asap,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,apple/swift-llvm,chubbymaggie/asap,chubbymaggie/asap,dslab-epfl/asap,dslab-epfl/asap,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap