Resolve or eliminate Environment-related TODOs

Issue: SPR-8031, SPR-7508

org.springframework.beans/src/test/java/org/springframework/beans/factory/config/PropertyPlaceholderConfigurerTests.java

@@ -243,7 +243,6 @@ public class PropertyPlaceholderConfigurerTests {
 	}
 
 
-	// TODO SPR-7508: duplicated from EnvironmentPropertyResolutionSearchTests
 	@SuppressWarnings("unchecked")
 	private static Map<String, String> getModifiableSystemEnvironment() {
 		Class<?>[] classes = Collections.class.getDeclaredClasses();

org.springframework.beans/src/test/java/org/springframework/beans/factory/xml/ProfileXmlBeanDefinitionTests.java

@@ -30,9 +30,11 @@ import org.springframework.core.env.DefaultEnvironment;
 import org.springframework.core.io.ClassPathResource;
 
 /**
- * TODO SPR-7508: document
+ * Tests various combinations of profile declarations against various profile
+ * activation and profile default scenarios.
  *
  * @author Chris Beams
+ * @since 3.1
  */
 public class ProfileXmlBeanDefinitionTests {