Remove SecureMockMaker (elastic#127773)

The SecureMockMaker is a way for mockito to be allowed SM permissions
for proxying. Since the Security Manager is no longer used, secure mocks
are no longer needed. This commit removes them.

Author: rjernst

test/framework/src/main/java/org/elasticsearch/bootstrap/BootstrapForTesting.java

@@ -16,7 +16,6 @@
 import org.elasticsearch.core.Booleans;
 import org.elasticsearch.core.PathUtils;
 import org.elasticsearch.jdk.JarHell;
-import org.elasticsearch.test.mockito.SecureMockMaker;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -70,9 +69,6 @@ public class BootstrapForTesting {
             throw new RuntimeException("found jar hell in test classpath", e);
         }
 
-        // init mockito
-        SecureMockMaker.init();
-
         // Log ifconfig output before SecurityManager is installed
         IfConfig.logIfNecessary();
     }