test: simplify test skipping

* Make common.skip() exit.

  Also add common.printSkipMessage() for partial skips.

* Don't make needless things before skip

PR-URL: #14021
Fixes: #14016
Reviewed-By: Refael Ackermann <[email protected]>

Author: vsemozhetbyt

test/abort/test-abort-backtrace.js

@@ -1,13 +1,11 @@
 'use strict';
 const common = require('../common');
+if (common.isWindows)
+  common.skip('Backtraces unimplemented on Windows.');
+
 const assert = require('assert');
 const cp = require('child_process');
 
-if (common.isWindows) {
-  common.skip('Backtraces unimplemented on Windows.');
-  return;
-}
-
 if (process.argv[2] === 'child') {
   process.abort();
 } else {

test/addons/load-long-path/test.js

@@ -1,14 +1,12 @@
 'use strict';
 const common = require('../../common');
+if (common.isWOW64)
+  common.skip('doesn\'t work on WOW64');
+
 const fs = require('fs');
 const path = require('path');
 const assert = require('assert');
 
-if (common.isWOW64) {
-  common.skip('doesn\'t work on WOW64');
-  return;
-}
-
 common.refreshTmpDir();
 
 // make a path that is more than 260 chars long.