[ASan] Don't build the ASan runtime with -undefined dynamic_lookup, which isn't necessary anymore.
Fixes https://code.google.com/p/address-sanitizer/issues/detail?id=266.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@203572 91177308-0d34-0410-b5e6-96231b3b80d8