Fix determinism for app images

Clear the dalvik.system.DexFile cookie to make the long array
unreachable before the GC.

Test: test-art-host
Test: Ran 10x: mma -j40 && shasum $OUT/system/framework/oat/arm64/services.* && rm $OUT/system/framework/oat/arm64/services.* && rm $OUT/obj/JAVA_LIBRARIES/services_intermediates/oat/arm64/*

Bug: 34090128

Change-Id: I5a872de3e907461803a77254902d78ff6e657b43
2 files changed