Revert^2 "Remove hidden System.arraycopy(byte[]...."

This reverts commit 5857c9995cf66027e901c87980a7b0d2a3bb4e63.

Reason for revert: The problems with certain prebuilts that were still referencing the non-public / hidden method should now be dealt with under bug 130207940

Original description:

Remove hidden System.arraycopy(byte[]....

This method is hidden / not part of the public SDK API. Nobody should
be using it.

Bug: 128267537
Bug: 74103559
Change-Id: Id1b1786feb4ea114962d395f7c6beb5faf71a7e7
Test: build only
1 file changed