Move the test template to //testing/test.gni (part 2)

This CL move the test target from build/config/BUILDCONFIG.gn to testing/test.gni

It also update the test template to automatically build an apk on Android.

[email protected],[email protected]

Review URL: https://codereview.chromium.org/824263004

Cr-Commit-Position: refs/heads/master@{#312396}
diff --git a/net/BUILD.gn b/net/BUILD.gn
index 90bf394..f235c301 100644
--- a/net/BUILD.gn
+++ b/net/BUILD.gn
@@ -7,6 +7,7 @@
 import("//build/config/ui.gni")
 import("//build/module_args/v8.gni")
 import("//url/config.gni")
+import("//testing/test.gni")
 
 # TODO(cjhopman): //build/config/android/rules.gni also imports grit_rule.gni.
 # Currently, that file can't be imported multiple times.  Make this always