[ObjCARC] Turn off ignoring unwind edges in ObjCARC when -fno-objc-arc-exception is enabled due to it's affect on correctness.
[ObjCARC] Turn off ignoring unwind edges in ObjCARC when -fno-objc-arc-exception is enabled due to it's affect on correctness.

Specifically according to the semantics of ARC -fno-objc-arc-exception simply
states that it is expected that the unwind path out of a call *MAY* not release
objects. Thus we can have the situation where a release gets moved into a catch
block which we ignore when we remove a retain/release pair resulting in (even
though we assume the program is exiting anyways) the cleanup code path
potentially blowing up before program exit.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@172599 91177308-0d34-0410-b5e6-96231b3b80d8

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