test: fix sessions tests on 3.6 sharded clusters

SERVER-37631 requires that 3.6 servers have a command run on them
to report `logicalSessionsTimeoutMinutes` on connected proxies.

Author: mbroadst

test/config.js

@@ -35,6 +35,11 @@ class NativeConfiguration extends ConfigurationBase {
         console.log('[purge the directories]');
         return self.manager.start();
       })
+      .then(() => {
+        if (this.environment.server37631WorkaroundNeeded) {
+          return this.server37631Workaround();
+        }
+      })
       .then(function() {
         console.log('[started the topology]');
         return client.connect();
@@ -118,6 +123,26 @@ class NativeConfiguration extends ConfigurationBase {
   writeConcernMax() {
     return Object.assign({}, this.options.writeConcernMax || { w: 1 });
   }
+
+  server37631Workaround() {
+    console.log('[applying SERVER-37631 workaround]');
+    const configServers = this.manager.configurationServers.managers;
+    const proxies = this.manager.proxies;
+
+    const configServersPromise = configServers.reduce((result, server) => {
+      return result.then(() =>
+        server.executeCommand('admin.$cmd', { refreshLogicalSessionCacheNow: 1 })
+      );
+    }, Promise.resolve());
+
+    return configServersPromise.then(() => {
+      return proxies.reduce((promise, proxy) => {
+        return promise.then(() =>
+          proxy.executeCommand('admin.$cmd', { refreshLogicalSessionCacheNow: 1 })
+        );
+      }, Promise.resolve());
+    });
+  }
 }
 
 module.exports = NativeConfiguration;

test/environments.js

@@ -115,7 +115,8 @@ const genConfigNode = (port, options) => {
       options: {
         bind_ip: 'localhost',
         port: port,
-        dbpath: `${__dirname}/../db/${port}`
+        dbpath: `${__dirname}/../db/${port}`,
+        setParameter: ['enableTestCommands=1']
       }
     },
     options
@@ -126,7 +127,7 @@ const genConfigNode = (port, options) => {
  *
  */
 class ShardedEnvironment extends EnvironmentBase {
-  constructor() {
+  constructor(discoverResult) {
     super();
 
     this.host = 'localhost';
@@ -140,6 +141,9 @@ class ShardedEnvironment extends EnvironmentBase {
       return new Mongos([new Server(host, port, options)], options);
     };
 
+    const version =
+      discoverResult && discoverResult.version ? discoverResult.version.join('.') : null;
+    this.server37631WorkaroundNeeded = semver.satisfies(version, '3.6.x');
     this.manager = new ShardingManager({
       mongod: 'mongod',
       mongos: 'mongos'
@@ -157,11 +161,7 @@ class ShardedEnvironment extends EnvironmentBase {
     ];
 
     const configOptions = this.options && this.options.config ? this.options.config : {};
-    const configNodes = [
-      genConfigNode(35000, configOptions),
-      genConfigNode(35001, configOptions),
-      genConfigNode(35002, configOptions)
-    ];
+    const configNodes = [genConfigNode(35000, configOptions)];
 
     let proxyNodes = [
       {