For JIT-zygote config, add "apex" boot image files to the ART apex.

JIT-zygote boot image was split into primary and framework extension
in CL I5493e575ebf90bad1d5ad2850004d54590bbc079, but that CL forgot to
add JIT-zygote boot image files to the ART apex. Add them now.

Test: Steps 1-3:

  1. Temporarily enable Jit zygote in the product device config (in
    this case device/google/muskie/aosp_walleye.mk):

    +# System server should not contain compiled code.
    +PRODUCT_SYSTEM_SERVER_COMPILER_FILTER := verify
    +
    +# Use the apex image for preopting.
    +DEXPREOPT_USE_APEX_IMAGE := true
    +
    +# Have the runtime pick up the apex image.
    +PRODUCT_PROPERTY_OVERRIDES += \
    +    dalvik.vm.boot-image=/apex/com.android.art/javalib/apex.art:/system/framework/apex-framework.art

  2. Build and flash:
    $ lunch aosp_walleye-userdebug && m \
    && adb reboot bootloader && fastboot flashall -w

  3. Ensure that apex.art and apex-framework.art are mapped in the
    JIT-zygote address space:

    $ adb shell cat /proc/`adb shell ps | grep zygote64 | awk {'print $2'}`/maps | grep apex.art
    6ffde000-70102000 rw-p 00000000 00:00 0                                  [anon:dalvik-/apex/com.android.art/javalib/apex.art]
    701e5000-70262000 rw-p 00000000 00:00 0                                  [anon:dalvik-/apex/com.android.art/javalib/apex.art]
    72715cf000-72715d4000 r--p 000ba000 07:98 93                             /apex/com.android.art/javalib/arm64/apex.art

    $ adb shell cat /proc/`adb shell ps | grep zygote64 | awk {'print $2'}`/maps | grep apex-framework.art
    7084b000-70cc2000 rw-p 00000000 00:00 0                                  [anon:dalvik-/system/framework/apex-framework.art]
    70fd8000-71109000 rw-p 00000000 00:00 0                                  [anon:dalvik-/system/framework/apex-framework.art]
    7271517000-7271526000 r--p 00295000 fc:00 1268                           /system/framework/arm64/apex-framework.art

Change-Id: I985e15de9f38f345ba3e99451c6d9b8e2cb5d698