Bug 1649649 [wpt PR 24407] - Update wpt metadata, a=testonly

wpt-pr: 24407
wpt-type: metadata

testing/web-platform/meta/html/semantics/embedded-content/the-iframe-element/iframe-loading-lazy.tentative.html.ini

@@ -2,3 +2,9 @@
   [Test that iframes with loading='lazy' load once they enter the viewport.]
     expected: FAIL
 
+  [Below-viewport srcdoc iframes load lazily]
+    expected: FAIL
+
+  [Below-viewport iframes load lazily]
+    expected: FAIL
+