Delete unused imports in HeaderAssertionTests

Author: sbrannen

spring-test/src/test/java/org/springframework/test/web/servlet/samples/standalone/resultmatchers/HeaderAssertionTests.java

@@ -34,10 +34,6 @@
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
 import static org.springframework.test.web.servlet.setup.MockMvcBuilders.*;
 
-import java.text.SimpleDateFormat;
-import java.util.Locale;
-import java.util.TimeZone;
-
 /**
  * Examples of expectations on response header values.
  *