truffle: enable 200 optimizer runs on tests

truffle.js

@@ -5,5 +5,14 @@ module.exports = {
       port: 8545,
       network_id: "*" // Match any network id
     }
+  },
+  solc: {
+    optimizer: {
+      enabled: true,
+      // set to same number of runs as openst-platform
+      // so that integration tests on openst-protocol
+      // give accurate gas measurements
+      runs: 200
+    }
   }
 };