Add CommonOs to Config.Targets

Previously, CommonOs was not added to Config.Targets for the test which
caused AndroidMk to crash when trying to determine if a target needed
the 2ND_ prefix added to some make variables.

Bug: 245956352
Test: m nothing
Change-Id: Ia815537ee5ce8e83df9a01c57250aa888453d138
diff --git a/android/test_config.go b/android/test_config.go
index 0f88d51..de546c4 100644
--- a/android/test_config.go
+++ b/android/test_config.go
@@ -91,6 +91,9 @@
 		},
 	}
 
+	// Make the CommonOS OsType available for all products.
+	config.Targets[CommonOS] = []Target{commonTargetMap[CommonOS.Name]}
+
 	if runtime.GOOS == "darwin" {
 		config.Targets[config.BuildOS] = config.Targets[config.BuildOS][:1]
 	}