Use dist dir for test apks

Bug: 24494874
Change-Id: I1679c9f6981d9ac669d432679d0ba34c6680bb69
diff --git a/build.gradle b/build.gradle
index 3b23406..8e89705 100644
--- a/build.gradle
+++ b/build.gradle
@@ -34,7 +34,7 @@
 }
 
 ext.supportRepoOut = new File(buildDir, 'support_repo')
-ext.testApkDistOut = new File(buildDir, 'test_apks')
+ext.testApkDistOut = ext.distDir
 
 // Main task called by the build server.
 task(createArchive) << {