test: remove redundant common import

As the test-runner preloads `common` module, importing it in the test
is not necessary unless its properties are used. This commit removes
all such unnecessary imports.

Author: thefourtheye

test/internet/test-dns-txt-sigsegv.js

@@ -1,5 +1,4 @@
 'use strict';
-var common = require('../common');
 var assert = require('assert');
 var dns = require('dns');
 

test/internet/test-http-dns-fail.js

@@ -4,7 +4,6 @@
  * should trigger the error event after each attempt.
  */
 
-var common = require('../common');
 var assert = require('assert');
 var http = require('http');
 

test/internet/test-net-connect-timeout.js

@@ -3,7 +3,6 @@
 // https://groups.google.com/forum/#!topic/nodejs/UE0ZbfLt6t8
 // https://groups.google.com/forum/#!topic/nodejs-dev/jR7-5UDqXkw
 
-var common = require('../common');
 var net = require('net');
 var assert = require('assert');
 

test/internet/test-net-connect-unref.js

@@ -1,5 +1,4 @@
 'use strict';
-var common = require('../common');
 var assert = require('assert');
 var net = require('net');
 

test/message/2100bytes.js

@@ -1,5 +1,4 @@
 'use strict';
-var common = require('../common');
 var assert = require('assert');
 var util = require('util');
 

test/message/error_exit.js

@@ -1,5 +1,4 @@
 'use strict';
-var common = require('../common');
 var assert = require('assert');
 
 process.on('exit', function(code) {

test/message/eval_messages.js

@@ -1,6 +1,5 @@
 'use strict';
 
-var common = require('../common');
 var assert = require('assert');
 
 var spawn = require('child_process').spawn;

test/message/hello_world.js

@@ -1,5 +1,4 @@
 'use strict';
-var common = require('../common');
 var assert = require('assert');
 
 console.log('hello world');

test/message/max_tick_depth.js

@@ -1,5 +1,4 @@
 'use strict';
-var common = require('../common');
 
 process.maxTickDepth = 10;
 var i = 20;

test/message/nexttick_throw.js

@@ -1,5 +1,4 @@
 'use strict';
-var common = require('../common');
 var assert = require('assert');
 
 process.nextTick(function() {