SPR-8803 Refine UriComponentsBuilder.replaceQueryParam().

If no values are given, the query parameter is removed.

org.springframework.web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java

@@ -240,7 +240,7 @@ public class UriComponentsBuilderTests {
 		builder.replaceQueryParam("baz");
 		result = builder.build();
 		
-		assertEquals("baz", result.getQuery());
+		assertNull("Query param should have been deleted", result.getQuery());
 	}
 
 }