Add a CQ tester (which will start as experimental) with N5's on L.

masters/master.tryserver.chromium.linux/master.cfg

Index: masters/master.tryserver.chromium.linux/master.cfg
diff --git a/masters/master.tryserver.chromium.linux/master.cfg b/masters/master.tryserver.chromium.linux/master.cfg
index d0a0b7556aa702f34f52411d356a1be8db89a220..ec2c0fbadda7a75460fd5c9756ef8a4c5fd48672 100644
--- a/masters/master.tryserver.chromium.linux/master.cfg
+++ b/masters/master.tryserver.chromium.linux/master.cfg
@@ -79,6 +79,14 @@ b_android_compile_dbg = {
   'factory': m_annotator.BaseFactory('chromium_trybot'),
 }
 
+# combined builder/tester android recipes
+b_android_n5_rel_tests_recipe = {
+    'name': 'android_n5_rel_tests_recipe',
+    'factory': m_annotator.BaseFactory('android/tester'),
+    # Share build directory with compatible existing builders to save space.
+    'slavebuilddir': 'android',
+}
+
 b_android_compile_rel = {
   'name': 'android_compile_rel',
   'factory': m_annotator.BaseFactory('chromium_trybot'),
@@ -418,7 +426,8 @@ b_tools_build_presubmit = presubmit('tools_build')
 c['builders'] = [
   b_android_compile_dbg,
   b_android_compile_rel,
-  b_android_dbg_tests_recipe, b_android_arm64_dbg_recipe,
+  b_android_dbg_tests_recipe, b_android_n5_rel_tests_recipe,
+  b_android_arm64_dbg_recipe,
   b_android_fyi_dbg_tests_recipe,
   b_android_x86_dbg_recipe,
   b_android_clang_dbg_recipe,