Consider empty arrays as existent in JsonPath assertions

Prior to this commit, a JsonPath assertion that a path expression
evaluated to an array in JsonPathExpectationsHelper (and therefore
indirectly in JsonPathResultMatchers in Spring MVC Test) would
incorrectly fail if the array was present in the JSON content but empty.

This commit fixes this issue by removing the "not empty" check for
arrays and lists.

Issue: SPR-13320

spring-test/src/main/java/org/springframework/test/util/JsonPathExpectationsHelper.java

@@ -238,9 +238,6 @@ public class JsonPathExpectationsHelper {
 		Object value = evaluateJsonPath(content);
 		String reason = "No value for JSON path \"" + this.expression + "\"";
 		assertTrue(reason, value != null);
-		if (List.class.isInstance(value)) {
-			assertTrue(reason, !((List<?>) value).isEmpty());
-		}
 		return value;
 	}