[asan] use the slow CFI-based unwinder when reporting an error. Still use the fast unwinder for malloc/free. Linux-x86-only for now.
[asan] use the slow CFI-based unwinder when reporting an error. Still use the fast unwinder for malloc/free. Linux-x86-only for now.

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@172397 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