[asan] asan_device_setup improvements.
[asan] asan_device_setup improvements.

* Allow user SEGV handler if Android-L-like setup is detected.
  Necessary for correctness.
* Change file context labels on the wrapper script to appease SELinux.


git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@218124 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