Remove tests for asymptotic special-cases for tan() (#39803)

diff --git a/css/css-values/acos-asin-atan-atan2-computed.html b/css/css-values/acos-asin-atan-atan2-computed.html
index dc8ecce..bc547d5 100644
--- a/css/css-values/acos-asin-atan-atan2-computed.html
+++ b/css/css-values/acos-asin-atan-atan2-computed.html
@@ -43,7 +43,6 @@
 
 // Test nesting
 test_math_used('calc(cos(sin(acos(cos(pi)))))', '1', {type:'number', approx:0.1});
-test_math_used('calc(sin(atan(tan(pi/2))))', '1', {type:'number', approx:0.1});
 
 // Test types for atan2
 test_math_used('atan2(1px, -1px)', '135deg', {type:'angle', approx:0.1});
diff --git a/css/css-values/acos-asin-atan-atan2-serialize.html b/css/css-values/acos-asin-atan-atan2-serialize.html
index c867f34..8462fb2 100644
--- a/css/css-values/acos-asin-atan-atan2-serialize.html
+++ b/css/css-values/acos-asin-atan-atan2-serialize.html
@@ -44,8 +44,6 @@
     "atan(0.577350269)"                                 :"calc(30deg)",
     "atan(0)"                                           :"calc(0deg)",
     "atan(infinity)"                                    :"calc(90deg)",
-    "atan(tan(90deg))"                                  :"calc(90deg)",
-    "atan(tan(-90deg))"                                 :"calc(-90deg)",
     "atan2(37.320508075, 10)"                           :"calc(75deg)",
     "atan2(1s, 1000ms)"                                 :"calc(45deg)",
     "atan2(infinity, infinity)"                         :"calc(45deg)",
@@ -61,4 +59,4 @@
     test_serialization(exp, test_map[exp]);
     test_serialization(`calc(${exp})`, test_map[exp]);
 }
-</script>
\ No newline at end of file
+</script>