Fix flaky tests in SMTPMailSenderTest.java and ReflectionToStringBuilderUtilsTest.java (#6875)

Author: yannizhou05

utils/src/test/java/org/apache/cloudstack/utils/mailing/SMTPMailSenderTest.java

@@ -22,6 +22,7 @@
 import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
@@ -547,7 +548,7 @@ public void validateSMTPMailSenderCreateMessageSubjectContentAndContentTypeDefin
     public void setMailRecipientsTest() throws UnsupportedEncodingException, MessagingException {
         SMTPMessage messageMock = new SMTPMessage(Mockito.mock(MimeMessage.class));
 
-        Set<MailAddress> recipients = new HashSet<>();
+        Set<MailAddress> recipients = new LinkedHashSet<>();
         recipients.add(new MailAddress(null));
         recipients.add(new MailAddress(""));
         recipients.add(new MailAddress("  "));

utils/src/test/java/org/apache/cloudstack/utils/reflectiontostringbuilderutils/ReflectionToStringBuilderUtilsTest.java

@@ -175,17 +175,21 @@ public void validateGetNonSelectedFieldsNullObjectClassMustReturnNull(){
     public void validateGetNonSelectedFieldsObjectIsNotACollectionAndValidSelectedFieldsMustReturnNonSelectedFields(){
         String fieldToRemove = classToReflectRemovedField;
         String[] expectedResult = classToReflectFieldsNamesArray;
+        Arrays.sort(expectedResult);
 
         String[] result = ReflectionToStringBuilderUtils.getNonSelectedFields("test", fieldToRemove);
+        Arrays.sort(result);
         Assert.assertArrayEquals(expectedResult, result);
     }
 
     @Test
     public void validateGetNonSelectedFieldsObjectIsACollectionAndValidSelectedFieldsMustReturnNonSelectedFields(){
         String fieldToRemove = classToReflectRemovedField;
         String[] expectedResult = classToReflectFieldsNamesArray;
+        Arrays.sort(expectedResult);
 
         String[] result = ReflectionToStringBuilderUtils.getNonSelectedFields(Arrays.asList("test1", "test2"), fieldToRemove);
+        Arrays.sort(result);
         Assert.assertArrayEquals(expectedResult, result);
     }