Do not push a redundant value context in crankshaft.

src/hydrogen.cc

Index: src/hydrogen.cc
===================================================================
--- src/hydrogen.cc	(revision 8051)
+++ src/hydrogen.cc	(working copy)
@@ -5072,7 +5072,7 @@
     }
 
   } else if (ast_context()->IsValue()) {
-    CHECK_ALIVE(VisitForValue(expr->left()));
+    CHECK_ALIVE(Visit(expr->left()));
     ASSERT(current_block() != NULL);
 
     // We need an extra block to maintain edge-split form.
@@ -5085,7 +5085,7 @@
 
     set_current_block(eval_right);
     Drop(1);  // Value of the left subexpression.
-    CHECK_BAILOUT(VisitForValue(expr->right()));
+    CHECK_BAILOUT(Visit(expr->right()));
 
     HBasicBlock* join_block =
       CreateJoin(empty_block, current_block(), expr->id());