init: check the arguments of builtins during the build

Host init verifier already checks that the names and number of
arguments for builtins are correct, but it can check more.  This
change ensures that property expansions are well formed, and that
arguments that can be parsed on the host are correct.  For example it
checks that UIDs and GIDs exist, that numerical values can be parsed,
and that rlimit strings are correct.

Test: build

Change-Id: Ied8882498a88a9f8324db6b8d1020aeeccc8177b
diff --git a/init/service.h b/init/service.h
index cdf31bb..6f79faa 100644
--- a/init/service.h
+++ b/init/service.h
@@ -71,7 +71,8 @@
             const std::vector<gid_t>& supp_gids, int namespace_flags, const std::string& seclabel,
             Subcontext* subcontext_for_restart_commands, const std::vector<std::string>& args);
 
-    static std::unique_ptr<Service> MakeTemporaryOneshotService(const std::vector<std::string>& args);
+    static Result<std::unique_ptr<Service>> MakeTemporaryOneshotService(
+            const std::vector<std::string>& args);
 
     bool IsRunning() { return (flags_ & SVC_RUNNING) != 0; }
     Result<void> ExecStart();