Add more unit test for doh

Test: atest doh_unit_test
Bug: 155855709

Original change: https://android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/1676245

Change-Id: Idf0a7f695c877bc5818ab5fc81133d35a38925dc
(cherry picked from commit 36a05f5afd48099b0c3ff95c9d4e024a3de62239)
Ignore-AOSP-First: To solve the confict between mainline-prod and other branches with newer toolchain.
diff --git a/Android.bp b/Android.bp
index d33ab9a..9acc6e2 100644
--- a/Android.bp
+++ b/Android.bp
@@ -292,6 +292,13 @@
 }
 
 filegroup {
+    name: "resolv_rust_test_config_template",
+    srcs: [
+        "resolv_rust_test_config_template.xml",
+    ],
+}
+
+filegroup {
     name: "resolv_test_config_template",
     srcs: [
         "resolv_test_config_template.xml",
@@ -371,6 +378,9 @@
     edition: "2018",
     test_suites: ["general-tests"],
     auto_gen_config: true,
+    // Used to enable root permission for the test.
+    // TODO: remove after 'require_root' is supported in rust_test.
+    test_config_template: ":resolv_rust_test_config_template",
     rustlibs: [
         "libandroid_logger",
         "libanyhow",