suppress semicolons after do/while (#1556)

- unless both `beautify` & `screw-ie8` are enabled
- deprecate workaround for if-do-while-else

fixes #186

lib/output.js

@@ -784,7 +784,9 @@ function OutputStream(options) {
         output.with_parens(function(){
             self.condition.print(output);
         });
-        output.semicolon();
+        if (output.option("beautify") && output.option("screw_ie8")) {
+            output.semicolon();
+        }
     });
     DEFPRINT(AST_While, function(self, output){
         output.print("while");
@@ -917,15 +919,6 @@ function OutputStream(options) {
         // adds the block brackets if needed.
         if (!self.body)
             return output.force_semicolon();
-        if (self.body instanceof AST_Do) {
-            // Unconditionally use the if/do-while workaround for all browsers.
-            // https://github.com/mishoo/UglifyJS/issues/#issue/57 IE
-            // croaks with "syntax error" on code like this: if (foo)
-            // do ... while(cond); else ...  we need block brackets
-            // around do/while
-            make_block(self.body, output);
-            return;
-        }
         var b = self.body;
         while (true) {
             if (b instanceof AST_If) {