[MERGE #6092 @akroshg] Adding the Re-entrant macro

Merge pull request #6092 from akroshg:fix6050

The DeleteElement call can go to the user function, so we need to add a macro here.

Author: akroshg

lib/Runtime/Library/JavascriptArray.cpp

@@ -9292,7 +9292,7 @@ using namespace Js;
                 }
                 else
                 {
-                    JavascriptOperators::OP_DeleteElementI(obj, JavascriptNumber::ToVar(toVal, scriptContext), scriptContext, PropertyOperation_ThrowOnDeleteIfNotConfig);
+                    JS_REENTRANT(jsReentLock, JavascriptOperators::OP_DeleteElementI(obj, JavascriptNumber::ToVar(toVal, scriptContext), scriptContext, PropertyOperation_ThrowOnDeleteIfNotConfig));
                 }
 
                 fromVal += direction;