Remove layout tests that run execCommand on non-HTML documents

LayoutTests/svg/custom/bug79798.html

Index: LayoutTests/svg/custom/bug79798.html
diff --git a/LayoutTests/svg/custom/bug79798.html b/LayoutTests/svg/custom/bug79798.html
deleted file mode 100644
index 6e881e52492655acef1917ac308fd48492b31f5c..0000000000000000000000000000000000000000
--- a/LayoutTests/svg/custom/bug79798.html
+++ /dev/null
@@ -1,25 +0,0 @@
-<!-- This test passes if there is no crash. -->
-<!-- It was created by the fuzzer and has been reduced. -->
-<script>
-    function go() {
-
-        if (window.testRunner)
-            testRunner.dumpAsText();
-
-        q = document.getElementById('root').contentDocument;
-
-        r = document.createRange();
-        s = window.getSelection();
-
-        r.selectNodeContents( q.getElementById('g') );
-        s.addRange( r );
-
-        document.designMode = 'on';
-        q.execCommand('formatBlock', 1, 'h1');
-        q.execCommand('formatBlock', 1, 'h1');
-        q.execCommand('formatBlock', 1, 'h1');
-        document.open();
-        document.close();
-    }
-</script>
-<object data="resources/bug79798.svg" id="root" onload="go()"/</object>