Prepare target testing device setup for the move to the Runtime APEX.

Temporarily push a copy of the ICU data file into the Android Runtime Root
location ("/apex/com.android.runtime"). This step is required in the time
interval between:
1. the moment we stop setting `ART_TEST_ANDROID_RUNTIME_ROOT` to "/system"
   (meaning Bionic will start looking for it in the default
   `ANDROID_RUNTIME_ROOT` location, which is "/apex/com.android.runtime"); and
2. the moment we start installing and using the Runtime APEX (which includes
   the ICU data file) within the chroot directory on device for target
   testing.

Test: Rely on the ART Buildbot.
Bug: 121117762
Bug: 119293618
Change-Id: I5e91fc795e8bce32a6b21ca793839e6b68fe2eaf
3 files changed