Disallow empty token stream inside if() function

"if()" should be invalid parse time according to [0].

Move CSSInlineIfForStyleQueries flag to test.

Changed wpt tests using `if(){}` as non substitutable value.

[0] https://drafts.csswg.org/css-values-5/#if-notation

Bug: 346977961
Change-Id: I1112bc16f00043e6784213b0c00d19f0cc71dd20
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6197081
Commit-Queue: Munira Tursunova <[email protected]>
Reviewed-by: Anders Hartvoll Ruud <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1411577}

css/css-paint-api/registered-property-value-003.https.html

@@ -16,9 +16,9 @@
         inherits: false
       });
 
-      target.style.setProperty('--prop', 'if(){}');
+      target.style.setProperty('--prop', 'foo(){}');
 
-      expectWorkletValue(target, '--prop', '[CSSUnparsedValue if(){}]');
+      expectWorkletValue(target, '--prop', '[CSSUnparsedValue foo(){}]');
     } catch(e) {
       document.body.textContent = e;
       takeScreenshot();

css/css-properties-values-api/at-property.html

@@ -141,7 +141,7 @@
 test_descriptor('initial-value', 'rgb(1, 2, 3)');
 test_descriptor('initial-value', 'red');
 test_descriptor('initial-value', 'foo');
-test_descriptor('initial-value', 'if(){}');
+test_descriptor('initial-value', 'foo(){}');
 
 // initial-value: not computationally independent
 test_descriptor('initial-value', '3em', null, {'syntax': '"<length>"'});
@@ -191,7 +191,7 @@
 }
 
 // syntax, initialValue, inherits, expected
-test_applied('*', 'if(){}', false, 'if(){}');
+test_applied('*', 'foo(){}', false, 'foo(){}');
 test_applied('<angle>', '42deg', false, '42deg');
 test_applied('<angle>', '1turn', false, '360deg');
 test_applied('<color>', 'green', false, 'rgb(0, 128, 0)');