Allow dumpstate to read /system/bin executables.

On 64 bit systems, it's necessary to read the /system/bin executables
elf header to determine if it's a 32 bit or 64 bit executable to
contact the correct debuggerd service.

Bug: 17487122

(cherry picked from commit 04f3d79077fca1d11097895f0f6dbd57b4afa6d0)

Change-Id: Ib7835ffac1811a5aef54a250689287c1666720ef