Fixed isEmpty() for enumerables and strings and isNull() for object conversions to be applied only if it is the terminal method call as isEmpty() and isNull() return void.

src/test/resources/inspections/ObjectIsNullOrNotNull/ObjectIsNullOrNotNullBefore.java

@@ -12,5 +12,6 @@ public class ObjectIsNull {
         assertThat(new Object()).isNotEqualTo(null);
 
         assertThat(new Object()).as("foo").isNotEqualTo(null).as("bar").isEqualTo(new Object()).as("etc").isEqualTo(null);
+        assertThat(new Object()).as("foo").isEqualTo(null).as("bar").isEqualTo(new Object()).as("etc").isNotEqualTo(null);
     }
 }