Fix comments that are different from the action

Author: heowc

utils/src/main/java/software/amazon/awssdk/utils/StringUtils.java

@@ -302,7 +302,7 @@ public static String trimToEmpty(final String str) {
      * references are considered to be equal. The comparison is case sensitive.</p>
      *
      * <pre>
-     * StringUtils.equals(null, null)   = true
+     * StringUtils.equals(null, null)   = false
      * StringUtils.equals(null, "abc")  = false
      * StringUtils.equals("abc", null)  = false
      * StringUtils.equals("abc", "abc") = true

utils/src/test/java/software/amazon/awssdk/utils/StringUtilsTest.java

@@ -177,4 +177,13 @@ public void repeat_negativeCount_shouldThrowIae() {
     public void repeat_maxCount_shouldThrowOom() {
         StringUtils.repeat("a", Integer.MAX_VALUE);
     }
+
+    @Test
+    public void testEquals() {
+        assertFalse(StringUtils.equals(null, null));
+        assertFalse(StringUtils.equals(null, "abc"));
+        assertFalse(StringUtils.equals("abc", null));
+        assertTrue(StringUtils.equals("abc", "abc"));
+        assertFalse(StringUtils.equals("abc", "ABC"));
+    }
 }