[MERGE #790] fix for crash while processing asmjs var decl w/o a RHS

Merge pull request #790 from Krovatkin:norhs2
adding a nullptr check for a rhs node + unit test

Author: nmostafa

lib/Runtime/Language/AsmJsModule.cpp

@@ -854,6 +854,11 @@ namespace Js
                 mathFunc = nullptr;
                 simdFunc = nullptr;
 
+                if (!pnodeInit) 
+                {
+                    return Fail(decl, _u("The righthand side of a var declaration missing an initialization (empty)"));
+                }
+
                 if (pnodeInit->nop == knopName)
                 {
                     declSym = LookupIdentifier(pnodeInit->name(), func);

test/AsmJs/rlexe.xml

@@ -800,4 +800,11 @@
       <compile-flags>-testtrace:asmjs -maic:1</compile-flags>
     </default>
   </test>
+  <test>
+    <default>
+      <files>vardeclnorhs.js</files>
+      <baseline>vardeclnorhs.baseline</baseline>
+      <compile-flags>-testtrace:asmjs -maic:1</compile-flags>
+    </default>
+  </test>
 </regress-exe>

test/AsmJs/vardeclnorhs.baseline

@@ -0,0 +1,2 @@
+The righthand side of a var declaration missing an initialization (empty)
+Asm.js compilation failed.

test/AsmJs/vardeclnorhs.js

@@ -0,0 +1,10 @@
+//-------------------------------------------------------------------------------------------------------
+// Copyright (C) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
+//-------------------------------------------------------------------------------------------------------
+function module(stdlib) {
+    "use asm"
+    function foo() {
+        var abc;   
+    }
+}