Revert one Android change to java.util.Arrays.

This restores the original code from OpenJDK 8u121-b13. Looking more
carefully at the benchmark results (see the deepEquals results in the
commit message for http://r.android.com/670142) there is no evidence
that it improved anything.

Bug: 35910877
Test: Treehugger
Change-Id: I5d8b244374e659b1f6fb190c2665bc84ff7d7748