patchoat: add ability to verify relocated .art files

Patchoat can verify that a relocated .art file hasn't been modified
after generation using the --verify flag.

Test: adb shell /system/bin/patchoat --verify \
        --input-image-location=/system/framework/boot.art \
        --output-image-file=/data/dalvik-cache/arm64/system@framework@boot.art \
        --instruction-set=arm64
Bug: 66697305

Change-Id: If6ea02a0527381c520078cd6f3ae2c275a8a8ab1