Collect unit test results in test_android job

Summary:
Explicitly generate a XML file with unit test results, and convert this file to JUnit format for display in Circle.

Run in Circle: https://circleci.com/gh/hramos/react-native/1869

![screen shot 2018-03-28 at 12 07 15 pm](https://user-images.githubusercontent.com/165856/38050644-9712b6c6-3280-11e8-953c-a2eb722edf39.png)

[INTERNAL] [MINOR] [.circleci] - Collect, process, and display Android unit test results on Circle
Closes facebook#18608

Differential Revision: D7433151

Pulled By: hramos

fbshipit-source-id: 7c18b552d7790b238b4c2a720fb316dff8fd7ec3

scripts/circle-ci-android-setup.sh

@@ -41,14 +41,11 @@ function getAndroidNDK {
   if [ ! -e $DEPS ]; then
     cd $NDK_HOME
     echo "Downloading NDK..."
-    curl -o ndk.zip https://dl.google.com/android/repository/android-ndk-r10e-linux-x86.zip
-    curl -o ndk_64.zip https://dl.google.com/android/repository/android-ndk-r10e-linux-x86_64.zip
+    curl -o ndk.zip https://dl.google.com/android/repository/android-ndk-r10e-linux-x86_64.zip
     unzip -o -q ndk.zip
-    unzip -o -q ndk_64.zip
     echo "Installed Android NDK at $NDK_HOME"
     touch $DEPS
     rm ndk.zip
-    rm ndk_64.zip
   fi
 }