Also build the compile-time tests with _FORTIFY_SOURCE=3.

Bug: http://b/291762537
Change-Id: I01b15831ce44c722ed947f1b025f853ea29a5f81
diff --git a/tests/Android.bp b/tests/Android.bp
index 51afa55..aeb4587 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -1453,3 +1453,13 @@
         "-D_FORTIFY_SOURCE=2",
     ],
 }
+
+cc_library_static {
+    name: "bionic-compile-time-tests3-clang++",
+    defaults: [
+        "bionic_compile_time_tests_defaults",
+    ],
+    cppflags: [
+        "-D_FORTIFY_SOURCE=3",
+    ],
+}