This policy takes effect only when building with
SANITIZE_TARGET=address and allows the Zygote to load libraries from
/data. That's where ASan-instrumented copies of system libraries are
located. 32-bit library directories have been added a while back;
this CL extends the same policy to 64-bit directories.

Bug: 25751174

Change-Id: Ieb4701b78db9649ec8563f2962a69db537ae61b3