Allow out of range math functions result in random fixed value

[the spec](https://drafts.csswg.org/css-values-4/#calc-range) states
that "Parse-time range-checking of values is not performed within math
functions, and therefore out-of-range values do not cause the
declaration to become invalid".

This means we should allow math functions that result in out of range
results in <random-value-sharing> fixed values at parse time with the
expectation that they will be clamped at compute time

Author: Calme1709

css/css-values/random-computed.tentative.html

@@ -143,7 +143,7 @@
   }, `Property ${property} value on pseudo element '${pseudo_element}' '${specified}'${titleExtra ? ' ' + titleExtra : ''}`);
 }
 
-function test_random_computed_value_has_fixed(property, specified, minPercentage, maxPercentage, titleExtra) {
+function test_random_computed_value_has_fixed(property, specified, minPercentage, maxPercentage, expectedFixedValue = undefined, titleExtra = undefined) {
   test(() => {
     for (i = 0; i < iterations; ++i) {
       const target = document.getElementById('target');
@@ -164,8 +164,12 @@
       let [fixedString, fixedValue] = fixedComponent.split(' ');
 
       assert_equals(fixedString, 'fixed', specified);
-      assert_greater_than_equal(parseFloat(fixedValue), 0, specified);
-      assert_less_than(parseFloat(fixedValue), 1, specified);
+      if (expectedFixedValue) {
+        assert_equals(parseFloat(fixedValue), expectedFixedValue);
+      } else {
+        assert_greater_than_equal(parseFloat(fixedValue), 0, specified);
+        assert_less_than(parseFloat(fixedValue), 1, specified);
+      }
       assert_equals(minComponent, minPercentage, specified);
       assert_equals(maxComponent, maxPercentage, specified);
     }
@@ -260,6 +264,10 @@
 // Test unresolvable percentage values
 test_random_computed_value_has_fixed('translate', 'random(10%, 100%)', '10%', '100%');
 
+// Test out of range math functions for fixed value
+test_random_computed_value_has_fixed('translate', 'random(fixed random(1, 2), 10%, 100%)', '10%', '100%');
+test_random_computed_value_has_fixed('translate', 'random(fixed random(-2, -1), 10%, 100%)', '10%', '100%', 0);
+
 // Test random value sharing
 test(() => {
   const holder = document.createElement('div');

css/css-values/random-invalid.tentative.html

@@ -22,7 +22,6 @@
 test_invalid_value('width', 'random(element-shared 1px, 2px)');
 test_invalid_value('width', 'random(1px, 2px, 1px, element-shared)');
 test_invalid_value('width', 'random(--foo --bar, 1px, 2px)');
-test_invalid_value('width', 'random(fixed random(1, 2), 1px, 2px)');
 test_invalid_value('width', 'random(fixed 0.5 element-shared, 1px, 2px)');
 test_invalid_value('width', 'random(fixed 0.5 auto, 1px, 2px)');
 test_invalid_value('width', 'random(fixed 0.5 --foo, 1px, 2px)');