X87: Test for var declarations in eval which conflict with let

port d515e513(r31211).

contributed by zhengxing.li@intel.com

original commit message:
Previously, name conflicts between var and let declarations were only made into exceptions if they were visible at parse-time. This patch adds runtime checks so that sloppy-mode direct eval can't introduce conflicting var declarations. The change is implemented by traversing the scope chain when a direct eval introduces a var declaration to look for conflicting let declarations, up to the function boundary.

additional comment:
The original r31211 patch needs some additional changes for x87
1. Should use Smi::FromInt(variable->DeclarationPropertyAttributes())

BUG=

Review URL: https://codereview.chromium.org/1420683002

Cr-Commit-Position: refs/heads/master@{#31433}

src/full-codegen/x87/full-codegen-x87.cc

@@ -794,14 +794,14 @@ void FullCodeGenerator::VisitVariableDeclaration(
       } else {
         __ push(Immediate(Smi::FromInt(0)));  // Indicates no initial value.
       }
-      __ push(Immediate(variable->DeclarationPropertyAttributes()));
+      __ push(
+          Immediate(Smi::FromInt(variable->DeclarationPropertyAttributes())));
       __ CallRuntime(Runtime::kDeclareLookupSlot, 3);
       break;
     }
   }
 }
 
-
 void FullCodeGenerator::VisitFunctionDeclaration(
     FunctionDeclaration* declaration) {
   VariableProxy* proxy = declaration->proxy();
@@ -843,7 +843,8 @@ void FullCodeGenerator::VisitFunctionDeclaration(
       Comment cmnt(masm_, "[ FunctionDeclaration");
       __ push(Immediate(variable->name()));
       VisitForStackValue(declaration->fun());
-      __ push(Immediate(variable->DeclarationPropertyAttributes()));
+      __ push(
+          Immediate(Smi::FromInt(variable->DeclarationPropertyAttributes())));
       __ CallRuntime(Runtime::kDeclareLookupSlot, 3);
       break;
     }