Add `test_suites` to libutils_test.

Also move the singleton test out because our infrastructure can't cope
with tests that have their own test libraries.

Bug: http://b/124838889
Test: atest
Change-Id: Iddce3325a56d44a4288ace2a29921a3e02367413

libutils/Android.bp

@@ -205,7 +205,6 @@ cc_test {
         "LruCache_test.cpp",
         "Mutex_test.cpp",
         "SharedBuffer_test.cpp",
-        "Singleton_test.cpp",
         "String8_test.cpp",
         "StrongPointer_test.cpp",
         "Unicode_test.cpp",
@@ -240,17 +239,33 @@ cc_test {
         },
     },
 
-    required: [
-        "libutils_test_singleton1",
-        "libutils_test_singleton2",
-    ],
-
     cflags: [
         "-Wall",
         "-Wextra",
         "-Werror",
         "-Wthread-safety",
     ],
+
+    test_suites: ["device-tests"],
+}
+
+// TODO: the test infrastructure isn't yet capable of running this,
+// so it's broken out into its own test so that the main libutils_tests
+// can be in presubmit even if this can't.
+
+cc_test {
+    name: "libutils_singleton_test",
+    srcs: ["Singleton_test.cpp"],
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+    shared_libs: ["libbase"],
+
+    required: [
+        ":libutils_test_singleton1",
+        ":libutils_test_singleton2",
+    ],
 }
 
 cc_test_library {