[asan]: fix off-by-one error in stack unwinder (asan issue #44; reproduced thanks to 'csmith' fuzzer)
[asan]: fix off-by-one error in stack unwinder (asan issue #44; reproduced thanks to 'csmith' fuzzer)

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@152347 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt