Polish "Use String.repeat instead of explicit cycle"

See gh-31802

spring-core/src/main/java/org/springframework/asm/Type.java

@@ -462,7 +462,9 @@ public final class Type {
         return "double";
       case ARRAY:
         StringBuilder stringBuilder = new StringBuilder(getElementType().getClassName());
-          stringBuilder.append("[]".repeat(Math.max(0, getDimensions())));
+        for (int i = getDimensions(); i > 0; --i) {
+          stringBuilder.append("[]");
+        }
         return stringBuilder.toString();
       case OBJECT:
       case INTERNAL:

spring-core/src/main/java/org/springframework/cglib/core/ReflectUtils.java

@@ -218,7 +218,9 @@ public class ReflectUtils {
 			dimensions++;
 		}
 		StringBuilder brackets = new StringBuilder(className.length() - dimensions);
-        brackets.append("[".repeat(Math.max(0, dimensions)));
+		for (int i = 0; i < dimensions; i++) {
+			brackets.append('[');
+		}
 		className = className.substring(0, className.length() - 2 * dimensions);
 
 		String prefix = (dimensions > 0) ? brackets + "L" : "";