Fix bad assertion in css/css-typed-om/stylevalue-normalization/normalize-tokens.tentative.html (#35538)

This assertion could only fail.
diff --git a/css/css-typed-om/stylevalue-normalization/normalize-tokens.tentative.html b/css/css-typed-om/stylevalue-normalization/normalize-tokens.tentative.html
index 6dbc3e3..c83e093 100644
--- a/css/css-typed-om/stylevalue-normalization/normalize-tokens.tentative.html
+++ b/css/css-typed-om/stylevalue-normalization/normalize-tokens.tentative.html
@@ -57,7 +57,6 @@
 
   test(t => {
     assert_string_normalizes_to(t, 'margin', value, new CSSUnparsedValue(expectedResult));
-    assert_false(true);
   }, 'Normalizing "' + value + '" on a shorthand returns correct CSSUnparsedValue');
 
   test(t => {