Rename Android's cronet_unittests target to cronet_unittests_android.

We are introducing a cross-platform version of cronet_unittests,
initially for Linux, Mac and Fuchsia, so having the special Android-
specific test binary with the same name makes it impossible to set up
the GN isolate mapping correctly.

Bug: 808075
Cq-Include-Trybots: master.tryserver.chromium.android:android_cronet_tester;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I104259ab0ab9f3533600665555d67946bb39fcfc
Reviewed-on: https://chromium-review.googlesource.com/933591
Reviewed-by: John Budorick <[email protected]>
Reviewed-by: Andrei Kapishnikov <[email protected]>
Commit-Queue: Wez <[email protected]>
Cr-Commit-Position: refs/heads/master@{#538962}
diff --git a/BUILD.gn b/BUILD.gn
index 39af6a7..05f7e7ce 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -325,7 +325,7 @@
         "//components/cronet/android:cronet_sample_test_apk",
         "//components/cronet/android:cronet_test_apk",
         "//components/cronet/android:cronet_test_instrumentation_apk",
-        "//components/cronet/android:cronet_unittests",
+        "//components/cronet/android:cronet_unittests_android",
       ]
     }