Share vdex files in the ART apex between architectures (via symlinks).

Test: aosp_walleye-userdebug boots.

Test: Check symlinks to *.vdex files in the ART apex:
$ adb shell 'find /apex/com.android.art -name '*.vdex' | xargs ls -l'
  lrw-r--r-- 1 system system   23 1970-01-01 01:00 /apex/com.android.art/javalib/arm/boot-apache-xml.vdex -> ../boot-apache-xml.vdex
  lrw-r--r-- 1 system system   25 1970-01-01 01:00 /apex/com.android.art/javalib/arm/boot-bouncycastle.vdex -> ../boot-bouncycastle.vdex
  lrw-r--r-- 1 system system   23 1970-01-01 01:00 /apex/com.android.art/javalib/arm/boot-core-icu4j.vdex -> ../boot-core-icu4j.vdex
  lrw-r--r-- 1 system system   24 1970-01-01 01:00 /apex/com.android.art/javalib/arm/boot-core-libart.vdex -> ../boot-core-libart.vdex
  lrw-r--r-- 1 system system   19 1970-01-01 01:00 /apex/com.android.art/javalib/arm/boot-okhttp.vdex -> ../boot-okhttp.vdex
  lrw-r--r-- 1 system system   12 1970-01-01 01:00 /apex/com.android.art/javalib/arm/boot.vdex -> ../boot.vdex
  lrw-r--r-- 1 system system   23 1970-01-01 01:00 /apex/com.android.art/javalib/arm64/boot-apache-xml.vdex -> ../boot-apache-xml.vdex
  lrw-r--r-- 1 system system   25 1970-01-01 01:00 /apex/com.android.art/javalib/arm64/boot-bouncycastle.vdex -> ../boot-bouncycastle.vdex
  lrw-r--r-- 1 system system   23 1970-01-01 01:00 /apex/com.android.art/javalib/arm64/boot-core-icu4j.vdex -> ../boot-core-icu4j.vdex
  lrw-r--r-- 1 system system   24 1970-01-01 01:00 /apex/com.android.art/javalib/arm64/boot-core-libart.vdex -> ../boot-core-libart.vdex
  lrw-r--r-- 1 system system   19 1970-01-01 01:00 /apex/com.android.art/javalib/arm64/boot-okhttp.vdex -> ../boot-okhttp.vdex
  lrw-r--r-- 1 system system   12 1970-01-01 01:00 /apex/com.android.art/javalib/arm64/boot.vdex -> ../boot.vdex
  -rw-r--r-- 1 system system 1229 1970-01-01 01:00 /apex/com.android.art/javalib/boot-apache-xml.vdex
  -rw-r--r-- 1 system system 2043 1970-01-01 01:00 /apex/com.android.art/javalib/boot-bouncycastle.vdex
  -rw-r--r-- 1 system system 2883 1970-01-01 01:00 /apex/com.android.art/javalib/boot-core-icu4j.vdex
  -rw-r--r-- 1 system system  865 1970-01-01 01:00 /apex/com.android.art/javalib/boot-core-libart.vdex
  -rw-r--r-- 1 system system  395 1970-01-01 01:00 /apex/com.android.art/javalib/boot-okhttp.vdex
  -rw-r--r-- 1 system system 7125 1970-01-01 01:00 /apex/com.android.art/javalib/boot.vdex

Bug: 150934453

Change-Id: Ifbceb845749f4c218693f4118e8b35b59ff26de1