Remove hidden ArrayUtils usage in TetheringTest

Use CollectionUtils instead, which avoids using a hidden API.

Avoiding hidden API usage in tests is good in general, but this also
helps avoid jarjar problems where the com.android.internal.util package
is jarjared to some other package as some of its classes are included
in the module, and ArrayUtils cannot be found in the renamed package.

Bug: 192535368
Test: atest TetheringTest
Change-Id: I54dc8f6429d132a953ab1a674fe349fba4335936
1 file changed