eclipse-theiaGH-4532: Enabled parallel lerna execution on Win32

 - Aug 7, 2017: The parallel execution was bugusly introduced: e8beacc.
 - Nov 9, 2018: The logic was fixed: 5a60919.

`lerna` ran perfecetly without the sequential restriction for a year.
No need to punish Windows users with this build penalty.

This commit reverts e8beacc.

Closes eclipse-theia#4532

Signed-off-by: Akos Kitta <kittaakos@typefox.io>

scripts/lerna.js

@@ -18,17 +18,6 @@ const path = require('path');
 
 const lernaPath = path.resolve(__dirname, '..', 'node_modules', 'lerna', 'bin', 'lerna');
 
-if (process.platform === 'win32') {
-    console.log('Parallel lerna execution is disabled on Windows. Falling back to sequential execution with the \'--concurrency=1\' flag.');
-    if (process.argv.indexOf('--concurrency=1') === -1) {
-        process.argv.push('--concurrency=1');
-    }
-    const parallelIndex = process.argv.indexOf('--parallel');
-    if (parallelIndex !== -1) {
-        process.argv[parallelIndex] = '--stream';
-    }
-    console.log('Running lerna as: ' + process.argv.join(' '));
-}
 if (process.argv.indexOf('--reject-cycles') === -1) {
     process.argv.push('--reject-cycles');
 }