Fix variable name

Author: sbrannen

spring-test/src/main/java/org/springframework/test/context/cache/DefaultContextCache.java

@@ -239,8 +239,8 @@ private void putInternal(MergedContextConfiguration key, ApplicationContext cont
 		MergedContextConfiguration child = key;
 		MergedContextConfiguration parent = child.getParent();
 		while (parent != null) {
-			Set<MergedContextConfiguration> list = this.hierarchyMap.computeIfAbsent(parent, k -> new HashSet<>());
-			list.add(child);
+			Set<MergedContextConfiguration> set = this.hierarchyMap.computeIfAbsent(parent, k -> new HashSet<>());
+			set.add(child);
 			child = parent;
 			parent = child.getParent();
 		}