Rename APK tests workaround to make it more generic.

We plan to add junit tests running with Robolectric
so naming these files "apk" is slightly confusing.

NOTRY=True

Review-Url: https://codereview.webrtc.org/2020213002
Cr-Original-Commit-Position: refs/heads/master@{#12971}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 208d19845df447fdf8f85cab8fa5d0608253247e
13 files changed