feat: Only initialize BusinessCalendar caches when data is accessed and improve caching performance

Generators/src/main/java/io/deephaven/libs/StaticCalendarMethodsGenerator.java

@@ -79,6 +79,7 @@ public static void main(String[] args) throws ClassNotFoundException, IOExceptio
         excludes.add("description");
         excludes.add("firstValidDate");
         excludes.add("lastValidDate");
+        excludes.add("clearCache");
 
         StaticCalendarMethodsGenerator gen =
                 new StaticCalendarMethodsGenerator(gradleTask, packageName, className, imports,