improve process.exit() workaround (#2741)

- use public API
- fix issue with Node.js 0.10 on WIndows

test/ufuzz.js

@@ -6,11 +6,7 @@
 // bin/uglifyjs s.js -c && bin/uglifyjs s.js -c passes=3 && bin/uglifyjs s.js -c passes=3 -m
 // cat s.js | node && node s.js && bin/uglifyjs s.js -c | node && bin/uglifyjs s.js -c passes=3 | node && bin/uglifyjs s.js -c passes=3 -m | node
 
-// workaround for tty output truncation upon process.exit()
-[process.stdout, process.stderr].forEach(function(stream){
-    if (stream._handle && stream._handle.setBlocking)
-        stream._handle.setBlocking(true);
-});
+require("../tools/exit");
 
 var UglifyJS = require("..");
 var randomBytes = require("crypto").randomBytes;