use more obvious 100 >> 2 coonstant

Author: MaxGraey

std/assembly/date.ts

@@ -362,7 +362,7 @@ function dayOfWeek(year: i32, month: i32, day: i32): i32 {
 
   year -= i32(month < 3);
 
-  const century = floorDiv(year >> 2, 25);
+  const century = floorDiv(year >> 2, 100 >> 2);
   year += (year >> 2) + (century >> 2) - century;
 
   const monthOffset = <i32>load<u8>(tab + month - 1);