Add/use watchdog with standard timeout

Almost all uses of the watchdog use the same 500ms timeout, so add a new
method that assumes that.

Test: CtsKeystoreTestCases
Change-Id: Idf7852400a58ba954e4a71e5e2282734a0960072
diff --git a/keystore2/src/super_key.rs b/keystore2/src/super_key.rs
index 11ab734..1f9f5f8 100644
--- a/keystore2/src/super_key.rs
+++ b/keystore2/src/super_key.rs
@@ -919,10 +919,8 @@
                     &key_desc,
                     KeyType::Client, /* TODO Should be Super b/189470584 */
                     |dev| {
-                        let _wp = wd::watch_millis(
-                            "In lock_unlocked_device_required_keys: calling importKey.",
-                            500,
-                        );
+                        let _wp =
+                            wd::watch("In lock_unlocked_device_required_keys: calling importKey.");
                         dev.importKey(key_params.as_slice(), KeyFormat::RAW, &encrypting_key, None)
                     },
                 )?;