Bug 1728819 - set iframe_sandbox_window_open_download_block_downloads.tentative.html as intermittent on Linux opt. DONTBUILD

Test got added on Sep 03 in bug 1720857.

Differential Revision: https://phabricator.services.mozilla.com/D124613

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

@@ -1,13 +1,15 @@
 [iframe_sandbox_window_open_download_block_downloads.tentative.html]
   [window.open(download, ) triggering download in sandbox is blocked.]
     expected:
-      if (os == "linux") and fission and not debug: [PASS, FAIL]
+      if (os == "linux") and and not debug: [PASS, FAIL]
       if os == "android": FAIL
 
   [window.open(download, "_blank") triggering download in sandbox is blocked.]
     expected:
+      if os == "linux" and not debug: [FAIL, PASS]
       if os == "android": FAIL
 
   [window.open(download, "_blank", "noopener") triggering download in sandbox is blocked.]
     expected:
+      if os == "linux" and not debug: [FAIL, PASS]
       if os == "android": FAIL