repl: remove magic mode semantics

The workaround used in repl to support `let` and `const` in non-strict
mode (known as "magic" mode) has been unnecessary since V8 v4.9 /
Node.js v6.0.0. This commit functionally removes this workaround.

PR-URL: #11599
Refs: https://v8project.blogspot.com/2016/01/v8-release-49.html
Refs: https://github.com/nodejs/node/blob/master/doc/changelogs/CHANGELOG_V6.md#6.0.0
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Prince John Wesley <princejohnwesley@gmail.com>

lib/repl.js

@@ -78,10 +78,6 @@ exports.writer = util.inspect;
 exports._builtinLibs = internalModule.builtinLibs;
 
 
-const BLOCK_SCOPED_ERROR = 'Block-scoped declarations (let, const, function, ' +
-                           'class) not yet supported outside strict mode';
-
-
 class LineParser {
 
   constructor() {
@@ -266,7 +262,6 @@ function REPLServer(prompt,
     code = code.replace(/\n$/, '');
     code = preprocess(code);
 
-    var retry = false;
     var input = code;
     var err, result, wrappedErr;
     // first, create the Script object to check the syntax
@@ -277,9 +272,9 @@ function REPLServer(prompt,
     while (true) {
       try {
         if (!/^\s*$/.test(code) &&
-            (self.replMode === exports.REPL_MODE_STRICT || retry)) {
-          // "void 0" keeps the repl from returning "use strict" as the
-          // result value for let/const statements.
+            self.replMode === exports.REPL_MODE_STRICT) {
+          // "void 0" keeps the repl from returning "use strict" as the result
+          // value for statements and declarations that don't return a value.
           code = `'use strict'; void 0;\n${code}`;
         }
         var script = vm.createScript(code, {
@@ -288,17 +283,11 @@ function REPLServer(prompt,
         });
       } catch (e) {
         debug('parse error %j', code, e);
-        if (self.replMode === exports.REPL_MODE_MAGIC &&
-            e.message === BLOCK_SCOPED_ERROR &&
-            !retry || self.wrappedCmd) {
-          if (self.wrappedCmd) {
-            self.wrappedCmd = false;
-            // unwrap and try again
-            code = `${input.substring(1, input.length - 2)}\n`;
-            wrappedErr = e;
-          } else {
-            retry = true;
-          }
+        if (self.wrappedCmd) {
+          self.wrappedCmd = false;
+          // unwrap and try again
+          code = `${input.substring(1, input.length - 2)}\n`;
+          wrappedErr = e;
           continue;
         }
         // preserve original error for wrapped command