[asan] Fix asan-rt bitness issues in asan_device_setup on Android.

asan_device_setup script is using LD_PRELOAD to inject the ASan
runtime library into the Zygote process. This breaks when the Zygote
or any of its descendants spawn a process with different bitness due
to the fact that the ASan-RT library name includes the target
architecture.

The fix is to preload the library through a symlink which has the
same name in lib and lib64.

llvm-svn: 286188