deps: upgrade Mockito to support Java17 (#635)

* deps: upgrade Mockito to support Java17

Update Mockito to a version that supports the Java module system. This should enable
Java17 support.
Also cleans up one of the test files that failed for Java17.

Fixes the build error in #621

* test: do not restart mock server before each test

pom.xml

@@ -53,7 +53,7 @@
     <findbugs.version>3.0.2</findbugs.version>
     <threeten.version>1.4.4</threeten.version>
     <truth.version>1.1.3</truth.version>
-    <mockito.version>2.28.2</mockito.version>
+    <mockito.version>3.12.4</mockito.version>
     <hamcrest.version>2.2</hamcrest.version>
   </properties>
 
@@ -383,24 +383,6 @@
         </plugins>
       </build>
     </profile>
-    <profile>
-      <id>jdk17</id>
-      <activation>
-        <jdk>[17,)</jdk>
-      </activation>
-      <build>
-        <plugins>
-          <plugin>
-            <groupId>org.apache.maven.plugins</groupId>
-            <artifactId>maven-surefire-plugin</artifactId>
-            <configuration>
-              <!-- TODO: eventually this shouldn't be necessary after things are fixed. -->
-              <argLine>--add-opens java.base/java.io=ALL-UNNAMED</argLine>
-            </configuration>
-          </plugin>
-        </plugins>
-      </build>
-    </profile>
   </profiles>
 
   <reporting>