Fix x64 DEBUG build.

TBR=whesse@chromium

Review URL: http://codereview.chromium.org/6349049

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6578 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/lithium-x64.cc

@@ -653,7 +653,7 @@ LInstruction* LChunkBuilder::AssignEnvironment(LInstruction* instr) {
 
 LInstruction* LChunkBuilder::SetInstructionPendingDeoptimizationEnvironment(
     LInstruction* instr, int ast_id) {
-  ASSERT(instructions_pending_deoptimization_environment_ == NULL);
+  ASSERT(instruction_pending_deoptimization_environment_ == NULL);
   ASSERT(pending_deoptimization_ast_id_ == AstNode::kNoNumber);
   instruction_pending_deoptimization_environment_ = instr;
   pending_deoptimization_ast_id_ = ast_id;